The Service Tunnels

I secured my tool cases beneath the Navara's rear load cover at 03:15 that morning. I still had grease under my fingernails from the diesel work. That was how nearly every shift ended. Hands dirty, cases heavy.

There was that familiar ache across my shoulders from crawling around standby generator housings for the past ten hours. The night crew were already clearing out. I could hear voices echoing along the corridor, someone laughing at something that probably would not have been funny before hour nine of a night shift.

I fastened the load cover and checked it was locked. The weight of the tools and the place of each case felt familiar. Comforting, in a way. I knew exactly what I had and where everything was.

I had worked at Sellafield for six years. I was an electrician, mostly dealing with standby generators and breakers, with occasional instrumentation work when they needed another pair of hands. It was solid work.

Good pay. The sort of job where you turned up, did what needed doing and went home. No drama. Or that was how it used to be.

Lately, it had felt different. It was difficult to say exactly why. There was only this low hum of uncertainty that had begun creeping in perhaps three months earlier. Budgets tightened.

Contractors became quieter. Management started using words such as efficiency and restructuring in the monthly all-staff emails. I had seen it at other sites. Once you had moved around the nuclear industry enough, you learnt to read the signs.

So I kept my tools organised. Kept my pickup maintained. Kept my CV updated on the laptop in my flat in Whitehaven. Not that I had sent it anywhere yet.

Just in case.

I walked through the equipment room and passed the main desk, where Imran Shah was entering the shift handover notes. He did not look up. I did not say anything.

That was normal.

The cold struck as soon as I stepped outside. A freezing January night on the exposed Cumbrian coast, around minus 1 degree Celsius. The sky was clear and moonless.

There was only that great spread of darkness overhead and the security lights cutting white pools across the car park. My pickup stood in the third row, a 2009 Nissan Navara that ran well enough apart from a persistent coolant leak.

I climbed in and turned the key. The engine caught on the first attempt. Small mercies. I sat there for a moment and let the cab warm.

That was when my mind did what it always did after a shift. It began worrying at the work I had not quite finished.

The breaker problem at the Calder Reactor Complex was bothering me. We had been running load tests on the standby generators all week.

Standard work. Start the sets, simulate loss of the grid supply and make sure the automatic changeover switches did their job, with the standby power coming in cleanly. It should have been simple. I had done it a hundred times.

But the diesels kept tripping. Not every time, which would have made the fault easier to trace. Only often enough to establish a pattern.

The start sequence would begin normally. Fuel pressure good, oil pressure rising as it should. Then, halfway through the run-up, the breaker would open. No alarms and no fault codes.

Just a clean trip, as if something had told it to stop. I had checked the relay settings twice, removed the breaker panels and inspected every connection. I had replaced the control module on standby set two because I thought the logic board might be playing up.

Nothing changed. My supervisor, Malcolm Reed, told me to log it and move on. We had other work piling up. Even so, it stayed in my head.

I hated faults that made no sense. Diesel generators were meant to be simple and reliable. Give them fuel and air and they ran. If they did not run, there was a reason.

There was always a reason. I simply could not find it.

I put the Navara into reverse and backed out, still turning the problem over. Perhaps it was an earthing fault.

Perhaps the load bank had a short I had missed. Perhaps the breakers themselves were worn and needed replacing, even though they had tested properly on the bench. Perhaps I was thinking too hard about it. That was probably all.

I was halfway across the car park when I noticed Malcolm's Vauxhall Vivaro still outside the administration building. That was odd. He normally left the moment the handover was complete. I slowed.

I considered driving on. But Malcolm had always been decent with me, and if he was still there at 03:30, something was probably wrong. I pulled into the space beside his van and switched off the engine. The administration building door had been wedged open.

I found Malcolm in the corridor outside the security office, leaning against the wall with his arms folded. He looked tired. More than usual.

'Callum,' he said.

'All right. You heading off?'

'Yes.' He nodded.

For a moment, he said nothing. He simply stood there, deciding whether to say whatever came next.

'Keep your site pass on you,' he said at last.

I waited.

'Even when you're off site. Don't leave it in the pickup. Don't leave it at home. Keep it in your pocket.'

'All right,' I said.

I did not ask why. Malcolm was not the sort of man who said things without a reason, but he carried on anyway.

'Security are on edge,' he said. 'I don't know what's happening, but the Civil Nuclear Constabulary have been running extra armed patrols all week. Checkpoints at strange hours. They pulled Peter Hargreaves in yesterday for a pass audit that lasted three hours. Three hours for a man who's worked here fifteen years.'

I frowned. 'Did he get cleared?'

'Eventually. But they went through everything. His logs, his access history, even his personal vehicle registration. Turned routine paperwork into a full interrogation.'

'Did they say why?'

Malcolm shook his head. 'No, and I asked. They only said it was procedural. But it isn't. I've been here twenty-six years. This isn't procedural.'

I did not know what to say. Malcolm was the most scrupulously by-the-book supervisor I had ever worked under. If he thought something was wrong, it probably was.

'Just keep your pass on you,' he said again. 'And if they stop you, don't argue. Answer what they ask and nothing more.'

'Understood.'

He watched me for another second, then nodded and pushed himself away from the wall.

'Drive safely.'

'You too.'

I walked back to the Navara, and that low hum of uncertainty grew a little louder.

I left through the main gate at 03:40. The guard waved me out without even checking my pass. That was normal. Night shift, familiar face, Sellafield contractor sticker in the windscreen.

But I thought about what Malcolm had said.

Security are on edge.

Nothing looked on edge then. Everything felt dead quiet.

I joined the A595 towards Whitehaven, following the dark Cumbrian coast. There were miles of empty road ahead, with the site and the black edge of the sea behind me. I had driven the route perhaps a thousand times. I knew every pothole, every bend and every place where sheep sometimes got through a fence.

The plan was tea and bed, in that order.

There was a 24-hour petrol station on Loop Road South in Whitehaven. I would buy a large takeaway tea, drive the last few minutes to my flat and sleep for six hours before I had to think about anything else.

That was the plan.

My headlights cut a tunnel through the darkness. The road belonged to me. There was not another vehicle in sight.

I switched on the radio. BBC local radio was carrying a discussion about livestock prices. I left it on. The noise helped.

My thoughts drifted back to the breaker fault. I began walking through the wiring diagrams in my head, tracing the load paths and trying to see what I had missed.

Then I saw the lights.

Brake lights. A lot of them.

They were clustered perhaps two miles beyond the Sellafield turn-off, in a stretch where there was very little except fields and darkness. I eased off the accelerator and rolled nearer.

Red-and-white Chapter 8 road barriers and traffic cones had been placed across both lanes, funnelling vehicles through a single narrow point. Four or perhaps five people stood in front of them wearing dark armed-police kit and deliberately unmarked body armour. They carried carbines in their hands rather than slung across their backs.

Torch beams swept windscreens as they brought vehicles forward one at a time. There were brief exchanges I could not hear from where I sat.

They were not ordinary roads policing officers, and something about them did not look like a normal CNC patrol either. Wrong markings, wrong position. I did not know who they were.

The car ahead was sent through. I rolled forwards.

My heart quickened slightly. It was not panic, only the alertness that comes when something does not fit.

One of the armed officers stepped into my lane and raised a hand. I stopped.

He walked towards the Navara. Tall, solidly built, carbine held ready but not aimed. There were no identifying patches on his body armour. He wore gloves and a radio headset.

He moved with the particular economy of someone accustomed to armed work. I lowered my window.

He stopped beside the door and shone his torch across my face, then down into the cab. He had grey eyes, an angular jaw and a thin scar passing through his left eyebrow.

'Where have you come from?'

His voice was flat and commanding. He was not really asking. He was confirming.

'Sellafield,' I said. 'I've just finished my shift.'

He did not reply. He continued looking at me.

I waited.

'Step out of the vehicle.'

I did as I was told. He kept the torch on me and barely blinked.

'There's been an ammonia leak from an industrial refrigeration plant,' he said in the same flat tone. 'The release is drifting towards Whitehaven. We're turning traffic around.'

I stood beside the Navara with my hands visible.

An ammonia leak.

That ought to have made some sense. Sellafield dealt with plenty of unpleasant substances. But there was no industrial refrigeration plant using ammonia anywhere near the section where I had been working that night.

We dealt with standby generators, electrical systems and instrumentation. Nothing in my work area involved an ammonia refrigeration system.

I did not say that. I simply nodded.

The officer shifted half a step back, turning his body so the carbine remained between us. It was not pointed at me. It was merely present.

'Turn your vehicle around and return to Whitehaven by a diversion.'

'Understood,' I said.

He moved the light from my face and swept it once more through the cab. Thermos in the cup holder, old paperwork by the handbrake, nothing of interest. Then he stepped back towards the barriers and signalled to someone I could not see.

I got in and raised the window.

My hands were steady. That surprised me slightly.

I reversed about 3 metres before turning the pickup in a broad arc. The vehicles behind me were doing the same, their headlights sweeping fields and dry-stone walls as they manoeuvred. Nobody spoke. Nobody asked questions.

Once the Navara was pointing back the way I had come, I started moving.

The wind struck the windscreen at an angle, driving salt mist and loose grit inland from the coast. I watched it pass through the headlight beams, moving from the sea towards the site.

If an ammonia cloud was drifting towards Whitehaven, the wind was carrying it the wrong way. Whitehaven lay away from the site. The salt mist and grit were being driven inland, back towards the restricted area.

I kept driving.

Perhaps I was mistaken. Perhaps the wind had shifted during the past hour. Perhaps there was some local pattern around the buildings and coastline that I did not understand.

But I had driven that road five nights a week for six years. The prevailing wind did not change its mind that neatly.

I took my mobile phone from my jacket pocket, keeping one hand on the wheel. I meant to check the weather and see whether an official alert had been issued.

There was no service.

I watched the screen. One bar appeared, vanished and returned.

Flickering.

I had had a full signal two miles earlier. Coverage could be uneven around the site, but there was usually something. This was different.

I put the phone in the cup holder and continued. The road bent gently with the land. I could see three or four other vehicles ahead, all travelling back towards the last junction. Behind me, the checkpoint had become an orange-white glow in the mirrors.

My work radio was still clipped to my belt. I had forgotten about it. Most nights I switched it off after clocking out, but that night I had not bothered.

I reached down and turned up the volume.

Static.

I cycled through the channels. The maintenance frequencies were quiet. The security frequencies were quiet.

Then I reached the emergency band and heard a burst of sound that was not static.

'Need backup at the MEF north access. We have a...'

A man's voice. Tight. Frightened, perhaps.

Then it cut out.

I left the radio on that channel and waited.

Nothing. Only dead air.

I glanced in the rear-view mirror. The checkpoint was still visible, perhaps half a mile behind me. Carbines showed as dark lines against the barrier lights.

The scarred officer who had spoken to me was still standing in the road.

I faced forwards again. The radio hissed.

I did not like any of it. The checkpoint made no sense. The ammonia story made no sense. Now the emergency band was coming alive and falling silent, which made even less sense.

Malcolm's warning returned to me.

Security are on edge. Extra armed patrols. Checkpoints at strange hours.

Yes. Strange hours.

I reached for the light switch and killed my headlights.

The road vanished ahead of me, leaving only the faint glow of the dashboard and the thin ambient light of the stars. I could still make out the tarmac. Barely.

I slowed to about 30 miles per hour and carried on.

None of the vehicles behind me did the same. Their headlights remained on. I watched them spread apart in the mirror as they took different routes towards Whitehaven.

I was not going back to Whitehaven.

At the next turn, I took Calder service road, which ran along the inner fence line. It was not gated or ordinarily restricted. It was simply a maintenance access road that followed the southern perimeter for roughly eight miles before reaching another junction.

I had used it when traffic was backed up, or when I needed to reach the eastern technical area without making the full loop. The surface was rougher than the A595, with cracked tarmac and patches of gravel. The Navara managed it easily.

I kept the lights off.

On my right, the security fence ran parallel to the road, roughly 100 metres away. Chain-link, nearly 4 metres high, topped with coils of razor wire. Beyond it, the site opened into low buildings, access roads and the taller shapes of the reactor complexes.

I could see some of them from there. Towers, dark blocks of secured buildings and a scattering of security lamps that cast yellow pools over empty ground.

There was no movement.

I carried on, aiming to work my way south. If I remained on Calder service road long enough, I could cut towards Egremont. From there, I could pick up the A5086 and loop back to Whitehaven from the east.

It would add perhaps forty minutes, but it would take me around the checkpoint, assuming that was the only one.

I did not know why I was assuming that.

The radio crackled again. I turned it up.

'Kestrel, this is Hannah. Do you copy?'

A woman's voice, clipped and rapid. I recognised the cadence of site control.

'Kestrel, this is Hannah. Respond.'

Silence.

'Kestrel, this is site control. Please respond.'

Her voice became sharper. Not louder, only tighter.

I kept my eyes on the road, but one hand remained near the radio.

'Kestrel, if you can hear this, we have multiple calls from the MEF. We need confirmation of your status.'

The Materials Examination Facility. That was in the eastern technical area, perhaps four miles from where I was.

'Kestrel, please respond.'

Nothing.

I slowed and let the Navara coast. The road ahead was empty. The fence line to my right was empty.

Everything out there was empty.

'Owen Mercer, this is Hannah Cole, site control. If you are receiving this transmission, key your radio twice.'

Silence.

Then she said, 'Any Civil Nuclear Constabulary armed patrol, this is site control. I need confirmation of unit Kestrel's last known position. Respond on this channel.'

Her voice cracked slightly on the last word. Not much, but enough.

I waited.

Nobody answered.

'This is site control. Any armed patrol, please respond.'

Dead air.

I looked across at the site. The buildings remained. The lights remained on.

But nobody was talking.

Hannah's voice returned, tighter still.

'This is Hannah Cole, site control, calling any available unit. We have an active emergency at the Materials Examination Facility and I need immediate confirmation of personnel status in that sector.'

A pause.

'Please respond.'

I kept driving. My hands had tightened around the steering wheel. The radio stayed loud as I watched the dark fence slide past.

Hannah continued calling for Kestrel at intervals of perhaps thirty seconds. At first she sounded professional, then increasingly strained. She would use the call sign, wait, then try his full name.

Owen Mercer.

As if both names might make him answer.

I slowed to around 20 miles per hour. I did not want to miss anything on the radio, and I did not want to hit a pothole I could not see without headlights.

Then the channel clicked and somebody breathed hard into a microphone.

'Dispatch.'

The voice was ragged. Male. Short of breath.

'This is Kestrel.'

I took my foot off the accelerator and let the pickup roll.

Hannah answered at once.

'Kestrel, what is your status? I've been calling for-'

'I'm at the shielded-cell building.'

He was still breathing heavily, but not as if he had been running. It sounded more like he had been fighting.

'There's an intruder inside the building. We engaged, but-'

Static swallowed the next few words. When it cleared, Owen was still speaking.

'...won't go down. Carbine fire isn't stopping it.'

It.

Not him. Not them.

I waited for Hannah to ask what he meant.

She did not.

She only said, 'Copy. I'm sending backup to your position. Stay on this channel.'

'Negative.' Owen's voice fractured slightly. 'Do not send anyone inside. We're falling back to-'

The microphone popped.

It was not static. It was something else.

A wet, tearing sound came through the speaker and made me flinch.

Then the channel died.

I stared at the radio clipped to my belt.

Hannah called his call sign again. Then his name.

There was no answer.

I took my mobile from the cup holder. One bar still flickered on and off. I tried opening a browser anyway, but nothing loaded. There was only a turning symbol on the screen.

I put it down again.

The road ahead divided. Straight on would keep me on Calder service road for another three miles before the junction. To the left lay a gravel maintenance track I had used perhaps a dozen times during outage work. It led towards utility access points and the underground service routes without following the exposed main roads.

It was faster if you knew it was there. Rougher, but direct.

I thought about what I had heard.

An intruder that carbine fire would not stop. Owen calling it 'it'. Hannah not questioning the word. Armed personnel at a checkpoint, concealing their identities and telling me a story about ammonia that did not fit. Malcolm warning me to keep my pass because security had become nervous.

None of it added up to anything I understood.

All of it added up to something being badly wrong.

I turned left onto the gravel track. The Navara's suspension rattled over the uneven surface.

I kept my speed down to about 15 miles per hour and peered through the windscreen. The headlights remained off. If anyone was looking, I did not want them seeing me.

The track ran for about half a mile before it reached a maintenance gate. It was chain-link, almost 4 metres high like the perimeter fence, with a padlock and chain threaded through the frame.

I had passed through it before. Maintenance had the combination.

I slowed as I approached, ready to stop and get out.

The chain lay on the ground.

I stopped roughly 6 metres short and stared at it. One end was still looped through the gate. The other had been cut cleanly.

It had not rusted through or snapped.

It had been cut.

I put the Navara into neutral and sat with the engine idling. The radio remained silent.

Hannah had stopped calling.

The gate stood open by about a metre. Enough for a person to pass through. Enough for the Navara if I took it at the right angle.

I looked beyond it along the track. My eyes had adjusted well enough to distinguish shapes beneath the stars. About 50 metres farther in, something large stood off to one side. Pale and box-shaped.

It looked like a vehicle.

I checked my mobile once more. No service.

I considered reversing, turning around and staying on Calder service road until I reached somewhere with working phone coverage.

That would have been the sensible thing to do.

Probably.

Instead, I put the Navara into gear and edged through the cut gate. Gravel crackled beneath the tyres.

I moved forwards slowly, still without headlights, and the pale shape became clearer.

It was a marked Civil Nuclear Constabulary Mitsubishi Shogun.

The Shogun stood at an angle across the track as if somebody had stopped in a hurry. Both front doors were open, hanging wide. The interior light cast a weak pale wash across the gravel.

I stopped about 3 metres behind it and switched off the engine.

For several seconds, I stayed in the driver's seat and listened.

Wind pushed salt mist and grit across the track. I heard my own breathing.

Nothing else.

I reached for the heavy rechargeable inspection torch in the door pocket. It was solid enough to serve as a lever if I needed one.

I climbed out, my boots landing on gravel, and eased the door shut without letting it slam.

The air was bitter, around minus 1 degree Celsius. My breath showed white before my face.

I approached the Shogun with the torch in my right hand but did not switch it on. I told myself there had been an accident, or that officers had responded to something and abandoned the vehicle in a hurry.

Perhaps they had gone on foot to deal with whatever Owen had encountered.

I stopped beside the driver's door and looked inside.

The keys remained in the ignition. A radio handset hung from the dashboard by its coiled lead. There was a thermos in the cup holder and paperwork clipped to a board on the passenger seat.

No blood. No obvious damage.

Simply empty.

I stepped back and examined the area. Dirt, gravel and coarse grass. The fence line stood roughly 30 metres to my right. A utility corridor hatch lay another 20 metres ahead, a concrete square set into the ground beneath a steel cover.

Then I saw the boots.

They protruded from behind the Shogun's rear passenger-side wheel. Work boots. Tan leather with composite toes, the sort half our crew wore.

My chest tightened.

I switched on the torch and went around the back of the vehicle.

The boots were attached to legs. The legs belonged to a body lying face down in the dirt.

I recognised the boots first. There was a distinctive scuff on the left one where Jamie had caught it against a cable tray two months earlier. He had complained for a week because the boots were new.

Jamie Fletcher. Journeyman electrician. Same crew as me.

Thirty-one years old. Engaged. Lived in Cleator Moor. Drove a Vauxhall Vivaro with recurring clutch trouble.

I raised the beam.

He still wore his work jacket, with the Sellafield contractor branding across the back.

But the jacket had been torn.

Not torn. Split.

A vast wound ran from his left shoulder blade to his lower back. It was wide enough for me to see inside him. Ribs. Tissue. Things that should have been covered and held together by skin.

It looked as though something had pulled him apart.

I stood with the torch beam fixed on Jamie's back and did not move.

My mind tried to force what I saw into some explanation I could understand. An animal attack. An industrial accident.

Something.

Nothing fitted.

I crouched, keeping the light on him. His right arm lay out to one side, fingers curled into the dirt. He was not wearing gloves. I could see the engagement ring he had begun wearing on a chain looped around his wrist because site rules would not let him keep it on his finger while working.

The wound was no longer bleeding. Perhaps it had stopped. Perhaps there was no blood left to lose. The ground beneath him was dark and sodden.

I reached out, though I did not know why, and touched his wrist.

Cold. Stiff.

I withdrew my hand.

That was Jamie.

That was all that remained.

A boot scraped against gravel behind me.

I turned and brought up the torch.

The beam caught a man standing at the rear of the Shogun with a pistol aimed directly at my chest. He wore CNC dark armed-police kit and body armour. A trauma pouch was fixed at his hip.

His dark eyes did not leave me.

'Don't move,' he said.

I stayed still. The pistol remained steady.

'Site pass. Slowly.'

Still crouched, I shifted my weight and used my free hand to draw the Sellafield contractor pass from my jacket pocket. I held it up. The laminated card twisted on its lanyard in the cold wind.

He advanced two controlled steps, glancing from my face to the pass and back. The pistol did not move.

He was lean, with short black hair and sharp cheekbones, perhaps in his mid-thirties. The tape on his body armour read 'OKAFOR'.

'Electrician?' he asked, reading the pass.

'Yes.'

'You know him?'

He inclined his head towards Jamie's body without looking away from me.

'Jamie Fletcher. He's on my crew.'

Okafor's jaw tightened. He lowered the pistol by a few centimetres.

'Are you armed?'

'No.'

'Turn around. Stand up slowly.'

I rose with the torch pointed at the ground. Okafor moved in and searched my jacket, waistband and pockets, then checked my work belt. He was quick and methodical.

He stepped away.

'You came through the roadblock.'

'I turned round, took Calder service road, then came in through the cut maintenance gate.'

'Why?'

I did not answer at once. I was still trying to decide whether he meant to arrest me or shoot me.

He did not look panicked. He looked exhausted. His hands were steady.

'I heard the radio,' I said. 'Hannah calling for Kestrel. Then Kestrel said there was an intruder in the shielded-cell building. After that, nothing.'

Okafor's expression remained controlled, but something changed behind his eyes.

He holstered the pistol in one smooth movement, took a small torch from his belt and swept its beam over Jamie's body. He crouched to inspect the wound, then pressed his fingers to Jamie's neck for a pulse he plainly would not find.

'How long?' he asked.

'I don't know. He's cold.'

Okafor stood.

'The roadblock isn't there to protect anyone from what's happening,' he said. 'It's meant to keep civilians from entering the emergency zone.'

I waited.

'Cumbria Constabulary roads policing officers established the outer diversion an hour ago. The armed personnel you saw are part of a mixed CNC containment detail. Nuclear Decommissioning Authority emergency directive. All routes within a sixteen-kilometre radius are locked down. Everyone is turned back. No exceptions.'

'What about the ammonia leak?'

'A cover story. There is no ammonia release.'

I had already worked that out.

'So what is it?'

Okafor watched me for a long moment. Then he turned towards the utility access hatch and swept his torch over the concrete surround.

'We don't know. The intruder breached the perimeter at 23:38. It crossed three fenced zones without triggering a single alarm.'

I followed him. 'That's impossible.'

'Yes.'

He stopped by the hatch, crouched and ran gloved fingers along the edge of the steel cover.

'Surveillance didn't see it either. No visible image, no thermal trace. Only radio calls from patrols reporting contact before they went offline.'

'Kestrel?'

'Dead. Probably. Along with his partner and two more officers at the MEF.'

Okafor rose and faced me. His expression was blank and disciplined, but exhaustion showed around his eyes. He had clearly been moving for hours.

'It crossed the fence,' he said. 'Moved through restricted zones. Engaged armed officers. And it did all of that without appearing on any system we have.'

I thought about Jamie lying ten metres behind us. I thought about the wet tearing noise that had ended Owen's transmission.

'As if it understands the layout,' I said.

'Yes.'

'And the sensors.'

Okafor nodded once. 'Whatever it is, it knows this site.'

I did not like that. I did not like any of it.

I glanced at the Shogun, the cut gate and then Okafor.

'Are you out here alone?'

'My partner went to extract Sergeant Lewis Grant from the MEF. I stayed with the vehicle. That was forty minutes ago.'

'Have you got communications?'

'Intermittently. Mobile service is down across the whole site grid.'

I took out my phone. Still no bars. I put it away.

Okafor watched me. 'You said you heard Hannah on the radio.'

'Yes. Calling Kestrel, then calling anyone in the sector.'

'Did she get a response?'

'Only Kestrel. Then nothing.'

His jaw tightened. He looked north towards the distant glow of the reactor complex.

'The target's last confirmed position was the shielded-cell building twenty-two minutes ago. There has been no contact since.'

'So it could be anywhere.'

'Yes.'

I tried to think it through. An intruder that did not appear on cameras, motion detectors or thermal systems. Something that killed trained armed officers, tore Jamie open and left him in the dirt.

Okafor was still watching me.

'Why did you come back in?'

It was a fair question. I was not sure I had a fair answer.

'I heard the calls. I knew something was wrong.'

'So you drove towards it?'

'Yes.'

He studied me for another few seconds.

'Where were you trying to go?'

'I was going to head south, loop round towards Egremont and take the A5086 back to Whitehaven.'

'You know the site layout?'

'I've worked here six years. Electrical maintenance. Standby generators, breaker panels, some instrumentation.'

His expression changed slightly. He was thinking.

'Do you know the service routes?'

'Most of them. Generator rooms, service stairs, utility corridors.'

'Ways to reach the Calder Reactor Control Building without using the main roads?'

I considered the armoured distribution cables I had helped install, the maintenance routes used to move equipment across the site, and the old access tunnels linking substations, pump rooms and standby generator buildings.

'Yes,' I said. 'A few.'

Okafor watched me for a long moment. Then he passed me, returned to the Shogun and took the radio handset from the dashboard. He keyed it twice.

He waited.

Nothing.

He replaced the handset and turned to me.

'I need to reach the Calder Reactor Control Building,' he said. 'The main roads are blocked or being watched. If I go on foot, I'm exposed for two miles.'

I waited.

'You drive me in using the maintenance routes. I'll get you out afterwards.'

I looked at him, at the pistol on his hip and the trauma pouch beside it. Then I looked at Jamie's boots protruding from behind the Shogun.

'All right,' I said.

Okafor walked to the Navara and climbed into the passenger seat without another word.

I got in, placed the inspection torch in the cup holder and started the engine. Okafor fastened his seat belt, checked his pistol and returned it to the holster.

I reversed, steered around the abandoned Shogun and continued along the track.

'Keep the lights off,' he said.

'Already done.'

I drove by the glow of the instruments and the starlight. The gravel track grew rougher, corrugated by ruts and standing water. I held the Navara at about 20 miles per hour, both hands firm on the wheel.

Okafor braced one hand against the door and scanned the ground ahead.

'Stay parallel with the fence for another half-mile,' he said. 'Then turn west towards the substation access road.'

I knew the road. Old, cracked tarmac running behind the standby generator buildings where I had been working all week.

I nodded and drove on.

The radio on my belt crackled. Hannah's voice came through, faint and broken.

'Any unit, please respond.'

Okafor drew his own radio and pressed the transmit key.

'Okafor to control. I'm mobile, proceeding to CRC.'

Static answered.

Then Hannah's voice returned more clearly.

'Daniel, thank God. What's your status?'

'Uninjured. En route with a civilian contractor. ETA fifteen minutes.'

'A civilian? Daniel, you can't-'

'He knows the access routes. We're away from the main roads. I'll report when we're inside.'

Daniel released the key before Hannah could answer. He clipped the radio back to his belt and looked at me.

'You all right?'

'Yes.'

I turned left where the gravel track divided, taking the narrower branch that curved west. The fence receded behind us. Ahead, low utility buildings showed as dark shapes beneath the angular outline of a transformer enclosure.

The road deteriorated further. I slowed to 15 miles per hour.

Daniel said nothing. He kept watching the darkness.

I thought about the armoured distribution cable we had installed there during the November outage, running a three-phase supply from the substation to standby set five. The work had taken two days and left my back aching for a week.

The access road had been empty then. Only Imran and me, hauling drums on a flatbed.

Now it felt different.

Too quiet. No wind. No animals. Only the low engine note and the crunch of tyres over gravel.

I was about to speak when something struck the Navara.

It hit the covered load bed with a deep, buckling thud. The whole chassis rocked.

I stamped on the brake. The pickup skidded to a halt.

Daniel had his pistol out before we stopped moving. He twisted in his seat and peered through the rear window.

'What the hell was that?'

'I don't know.'

I switched off the engine and grabbed the inspection torch.

Daniel opened his door and stepped out, pistol raised as he swept the road behind us. I left by my side and went round to the rear.

The load cover was still shut. Nothing moved on it or around it. There was no shape in the road.

Nothing.

I switched on the torch and angled the beam across the cover and rear panel.

A fresh dent, perhaps 20 centimetres across, had been driven into the metal just to the right of centre. The paint was scraped and the panel buckled inwards.

Feathers clung to it.

They were wet, crushed into the surface, with dark streaks smeared across the dent.

I leant closer. The feathers were small, grey-brown and matted with something slick. I touched one. It came away on my glove and stuck there.

Daniel moved beside me, his pistol still trained on the surrounding darkness.

'What is that?'

'Feathers.'

'From what?'

'I don't know. A small bird, perhaps.'

I swept the light across the rest of the pickup.

There was nothing else. No blood. No body.

Only the dent and the feathers driven into the metal as though something powerful had struck it.

I stepped back. Daniel did the same.

We stood there looking from the Navara to the empty road and the black forms of the buildings ahead.

I switched off the torch.

Silence pressed in, heavy and wrong. Even the Navara sounded too quiet when I started it again.

The guard post at the Calder Reactor Complex access point appeared on our right about 50 metres ahead. Through the windscreen, I could make out a small concrete structure with one window facing the road and a yellow security lamp above the door.

The window was gone. It had not merely cracked or broken in one place. The whole frame had been forced outwards, scattering glass across the gravel in fragments and powder. The metal surround projected in sharp, twisted angles.

I slowed the Navara to 10 miles per hour and peered into the darkness.

Blood.

Blood was smeared across the jagged edges of what remained of the window. Dark streaks ran down the concrete wall beneath it, still wet enough to catch the yellow light. The pattern looked as though something, or someone, had been dragged straight through the opening rather than climbing through it.

Dragged.

The blood formed one continuous trail from inside the guard post to the ground outside.

I stopped the Navara about 6 metres back. Daniel leaned forward in the passenger seat, one hand braced against the door frame. For several seconds he said nothing. He only stared.

'That's Carter's post,' he said at last.

His voice was flat and professional, but I heard the strain underneath it. I kept both hands on the steering wheel.

'You know him?'

'Yeah.'

I waited. Daniel drew his pistol, checked it and held it low across his lap.

'Drive past. Don't stop.'

I put the Navara back into gear and rolled forwards at about 5 miles per hour. The headlights remained off.

The guard post passed on our right. I had a clearer view of the blood now, thick smears drawn horizontally across the broken window frame. The door hung open.

The light inside was still on. I saw an overturned chair, a radio handset on the floor with its coiled lead still attached, and more blood across the tiles. There was no body.

Daniel watched the post as we passed. He did not turn his head away until it had disappeared behind us.

The Calder Reactor Control Building stood about 180 metres ahead, three storeys of concrete and steel with narrow windows on the upper floors and a broad roller shutter at ground level for equipment access. Normally the entire building would have been lit, even at that hour. Shift crews worked around the clock.

That night, every window was dark apart from the dull red emergency lighting visible through the ground-floor glass.

I pulled up beside the personnel entrance and switched off the engine. Daniel was out before I had unclipped my seat belt.

I took the heavy rechargeable inspection torch from the cup holder and followed him. The personnel door had been propped open with a rubber wedge.

Daniel stopped at the threshold, pistol raised, and scanned the corridor beyond. I stood behind him with the torch switched off and waited.

The corridor ran roughly 9 metres ahead before turning left. Emergency lamps mounted near the ceiling at regular intervals cast everything in a murky red glow.

The air smelt wrong. Metallic and sharp.

I had encountered the smell before on jobs after somebody had been badly injured. Blood, adrenaline and something else I could not name.

Daniel entered. I followed two paces behind him.

The floor was scuffed lino, the same sort used in nearly every building on the Sellafield site. Chairs from the break room had been shoved into the corridor. Two lay on their sides, one with its backrest snapped. A clipboard had fallen face down near the wall, and I stepped over it.

Then I saw the carbine magazines.

Four of them were scattered across the floor, forming a trail that curved around the corner ahead. Two were empty. I could tell from the way they lay, light and hollow. The other two still held ammunition. A cartridge in one had jammed crooked between the feed lips.

I stopped.

Daniel had seen them as well. He crouched, picked up the nearest magazine, examined it and returned it to the floor. His expression did not change, but his jaw tightened.

Beyond the corner were long, dark scuffs like the marks left by boot heels being dragged backwards beneath a heavy weight. They continued for about 3 metres and then ended.

There was nothing beyond them but clean flooring.

Daniel reached the corner, checked the space beyond and waved me forwards. I followed him into a wider room.

It was the operations office, with desks arranged in rows, dead computer monitors and filing cabinets lining the rear wall. The emergency lighting was weaker there, and shadows gathered beneath the desks.

Daniel removed his radio from his belt and transmitted. Static answered him.

He changed channels and tried again. More static. He worked through maintenance, security and control, receiving nothing but dead air and occasional bursts of white noise.

Then he selected a frequency I did not recognise. It sounded like a higher band. He transmitted once.

A calm male voice came through.

'Identify.'

Daniel did not hesitate.

'Okafor, medic. Calder Reactor Control Building, ground floor.'

A pause followed.

'Confirmed. Status?'

'Two site personnel and one civilian contractor. Evacuation route compromised. Requesting guidance.'

The next silence was longer.

'Asset status?'

That word caught my attention.

Asset. Not intruder. Not suspect.

Asset.

Daniel glanced at me, then returned his attention to the radio.

'Unknown. Last visual twenty-three minutes ago, shielded-cell sector. No contact since.'

'Understood. Asset containment is priority. Do not engage. Confirm.'

Daniel's hand tightened around the radio.

'Confirmed.'

'Hold position. Containment team inbound. ETA thirty-five minutes.'

'Copy.'

The voice disappeared.

Daniel clipped the radio back onto his belt and looked at me.

'You catch that?'

'Yeah. Asset.'

'Yeah.'

Nothing more needed saying. This was not some random intruder who had found a way through the perimeter fence. They knew what it was. They had prepared a plan for it, and that plan had failed.

I held on to that thought.

Daniel moved farther into the operations office, pistol raised as he scanned the desks. I followed, leaving my torch off. My eyes had adjusted to the emergency lighting well enough to make out shapes and movement.

The first row of desks was empty. So was the second.

At the third, Daniel stopped and raised a closed fist.

I froze.

He pointed towards the back corner near the filing cabinets. A larger desk, probably the supervisor's station, had been shoved askew with one corner lifted from the floor. Beside it, a filing cabinet lay on its side with its drawers open and papers strewn around it.

A pair of black boots protruded from beneath the desk. They were safety boots issued to armed site personnel.

Daniel advanced slowly. I stayed close behind him.

The boots belonged to a man pinned beneath the desk, the fallen filing cabinet trapping his lower body. His chest rose and fell in shallow movements.

He was alive.

Daniel crouched, placed his pistol on the floor within reach and took a small torch from his body armour. He switched it on and directed the beam at the man's face.

There were sergeant's markings on his sleeve and GRANT printed on the identification tape across his armour.

Sergeant Lewis Grant.

I did not know him, but I had seen his name on shift rotas. His face was pale and wet with sweat. Blood covered part of his jaw and neck, and his eyes were half open. His right leg was twisted beneath him at an angle that tightened my stomach. It did not look like a simple break. The hip might have been dislocated, or the top of the femur might have fractured near the joint.

Daniel touched Lewis's neck and checked his pulse.

'Lewis, can you hear me?'

Lewis's eyes moved and focused on him. His mouth opened, but at first no sound emerged.

Then he managed a rasp.

'Daniel.'

'Yeah, I'm here. Stay still.'

Lewis tried to move his leg. His entire body went rigid and a strangled noise escaped his throat.

'Don't,' Daniel said. 'Don't move it. We're going to get this cabinet off you.'

I put my inspection torch on the floor and took one side of the filing cabinet. Daniel positioned himself opposite me.

We lifted on three.

The cabinet was heavy, perhaps 90 kilograms with its drawers still loaded. We raised it 15 centimetres, then nearly 30. Daniel wedged his boot beneath it, held the weight and shifted his grip higher.

'Again.'

We lifted. The cabinet cleared Lewis's legs, and we lowered it carefully to one side.

Lewis drew breath through clenched teeth. His leg remained badly twisted, but at least the weight was gone.

Daniel knelt beside him, opened the trauma kit on his armour and examined the leg without moving it. His hands were quick and methodical. He checked the hip, felt along the femur, looked for bleeding and tested around the knee.

'Femur's intact,' he said. 'Hip's dislocated. You're going to hate me in a minute.'

Lewis's breaths became faster, shallow and ragged.

'It was...' He stopped and swallowed. 'It was one target. Just one.'

Daniel took a pre-filled morphine auto-injector from the trauma kit and removed its cap.

'How many were in your team?'

'Four. Me, Asha Bennett, Tom Webb and Neil Carter.'

'Where are they?'

Lewis did not answer at once. His gaze shifted towards the corridor.

'Gone. It took Bennett first. Grabbed her through the doorway. Webb went after it. I heard him firing, then nothing.'

Daniel administered the morphine into Lewis's thigh.

'Carter?'

'Guard post. He called it in from there. Then his radio went dead.'

That matched the blood around the shattered window.

Daniel secured the used injector and watched Lewis's breathing for half a minute. It slowed slightly as the morphine began to work.

'I'm going to put the hip back in place,' Daniel said. 'It'll hurt. Then we move you.'

Lewis nodded. His jaw was clenched so tightly that I thought his teeth might crack.

Daniel positioned himself at the injured leg, one hand at the knee and the other around the ankle.

'On three. One.'

He pulled.

Lewis screamed, a short, sharp sound that ended when the joint went back into place with a noise I knew I would remember for the rest of my life.

Daniel held the leg steady for several seconds, then lowered it flat. Lewis gasped with his eyes squeezed shut, but his leg was straight again.

'Done,' Daniel said. 'Worst part's over.'

Lewis opened his eyes. His face had turned grey.

'It wasn't human.'

I stared at him.

'Started human-sized,' Lewis continued. His voice was steadier, although still thin. 'Torn disposable laboratory coveralls. We engaged from fifteen metres. Bennett put three rounds into the centre of its chest. It went down. Then it got back up.'

Daniel took out a rolled elastic bandage and began securing Lewis's knee.

'It dropped onto all fours,' Lewis said. 'Moved like...'

He stopped to breathe.

'Like a dog. Fast. Webb tried to track it, but it was already past him. Then it stood again. Upright. Taller than before.'

I said nothing.

'It listens,' Lewis said.

His eyes fixed on Daniel.

'For breathing. It knows where you are when you breathe.'

Daniel finished wrapping the knee and fastened the bandage.

'You're certain?'

'Yeah.'

Lewis's breathing had grown loud again, ragged and uneven. He heard it himself. His eyes widened.

'I can't... I can't stop.'

Daniel placed a hand on his shoulder.

'You're all right. We're moving now. Just stay as quiet as you can.'

But panic had taken hold. Lewis continued to breathe hard, each breath painfully clear in the silent room.

I looked at Daniel. He looked back.

Neither of us said what we were thinking. If the creature was still inside the building, it already knew where we were.

I pulled Lewis's left arm over my shoulders. Daniel took the right. It took three attempts to get him upright. On the third, Lewis bit down hard enough for me to hear his teeth click together. His breathing remained quick and shallow.

The stairwell lay beyond a door marked 'Utility Access Only', about 15 metres past the operations office through a service corridor where I had pulled cable half a dozen times. The door was already propped open. I did not ask whether Daniel had opened it earlier or whether somebody else had left it that way.

We manoeuvred Lewis through sideways, his weight dragging heavily on my shoulder.

The concrete-and-steel stairs descended beneath the building, with emergency lighting at every landing. There were thirty-two steps in all. I knew because I had counted them during the November outage, when we installed the armoured distribution cable supplying the backup panel on sublevel two.

Halfway down the second flight, Lewis made a noise that was not quite a word. Daniel told him we were nearly there.

We reached the landing and turned. The tunnel entrance was directly ahead.

A heavy blast door stood within a reinforced concrete frame. It required a site pass and a manual wheel to open. The door was half closed.

That was wrong. Those doors were either fully open or completely sealed. There was not meant to be an intermediate position.

Daniel stopped us about 1.5 metres away.

'Hold him.'

I adjusted my grip and took more of Lewis's weight while Daniel went forwards and crouched near the door. He drew his torch and swept its beam through the gap.

Something pale was wedged between the door and its frame.

It was not metal or rubber. It looked organic, smooth in places and ridged in others, with a texture like cartilage but much thicker.

Daniel holstered his torch, gripped the edge of the door with both hands and put his weight into it.

The pale obstruction flexed. It did not tear or break. It flexed.

The door shifted perhaps 20 centimetres and jammed again. Cold air rolled through the opening, damp and chemical. I smelt ozone and something sharper that might have been industrial coolant from the reactor systems.

Daniel braced one boot against the frame and pulled harder. The opening widened to about 30 centimetres.

'Get Lewis through.'

I half carried and half dragged him towards the gap. He tried to help, but the injured leg would not support him. I turned him sideways and forced him through, his body armour scraping against the frame.

Daniel held the door in place. Lewis stumbled through, and I followed beneath Daniel's arm. Daniel came last and released the door.

It swung back but did not close. The pale obstruction remained lodged in the gap.

The service tunnel extended in both directions beneath a low ceiling, with exposed conduit and pipework overhead. Emergency lamps at intervals of about 6 metres cast a dim red glow across wet concrete.

I had worked there five weeks earlier, replacing the emergency-lighting distribution box near the coolant sampling station. It had been routine work, two hours with a clipboard and a voltmeter.

The tunnel had been dry then.

Now every surface was slick, and I could feel moisture settling on my face.

Something moved in the shadows to our left.

I turned, pulling Lewis with me. Daniel had his pistol raised before I completed the movement.

A woman stepped into the light. She was about 1.6 metres tall and slim, with long black hair pulled back untidily. She wore light-blue laboratory clothing, soaked dark across the chest and sleeves. A Sellafield laboratory contractor pass hung crooked from a lanyard around her neck.

The pass identified her as Maya Ellison, laboratory technician.

I did not know her personally, but I had seen her name in access records when I worked near the Materials Examination Facility the previous year.

She stopped about 3 metres away with her hands raised and her palms visible. Her gaze travelled from me to Lewis, then to Daniel and back again.

'Are you heading up?' she asked.

Her voice was quiet and controlled, but it was the sort of control laid carefully over something much larger.

'Are you hurt?' Daniel asked.

Maya looked down at her soaked clothing and shook her head.

'It isn't blood. It's reactor coolant.'

She had been inside the coolant sampling room when the lockdown began, drawing routine samples from the primary loop. The doors had sealed and the ventilation had stopped without an alarm or warning. She had tried her radio and received nothing. The manual door release had refused to move.

So she had waited.

About twenty minutes after the lockdown, she had heard scraping in the ventilation duct above the sampling station. Then the grille had fallen and something had come through.

It had long limbs with joints at the wrong angles. It moved across the ceiling and dropped onto another technician, Kieran Doyle. Maya had been behind the sampling tanks. Kieran had been near the door.

The creature had grabbed him and pulled him apart. Not torn him. Pulled him apart, methodically.

Kieran had stopped making noise after about fifteen seconds.

'Is it still in there?' Daniel asked.

Maya shook her head.

'It left the same way it came in. Through the ventilation duct.'

She had waited another ten minutes before opening the coolant release valve and flooding the floor to knee height. If the creature returned, it would have to wade through contaminated reactor coolant to reach her.

Then, perhaps five minutes earlier, the door had opened without warning. She had come into the tunnel.

'Do you know what it is?' I asked.

Maya studied me for a long moment.

'Yes.'

She said it had begun as a Home Office research programme commissioned through the Nuclear Decommissioning Authority. Officially, it was a voluntary study of adaptability under controlled environmental, psychological and physical stress.

The subject had signed all the proper paperwork. It had remained voluntary until it was not.

'What does that mean?' Daniel asked.

'Containment failed. The subject changed.'

It had ceased responding according to baseline human behaviour. It had begun moving differently and thinking differently.

'Adaptive restructuring,' Maya said. 'That was the term used in the briefings. The reality is that it isn't human any more, and it knows this facility better than most of the people working here.'

Lewis made a sound, and I looked down. His eyes were open and more focused than before.

'It knew where to go,' he said. 'It avoided our patrols. Used the service corridors and maintenance shafts. It knew.'

The lights overhead flickered.

Not all of them. Only the section behind Maya, farther along the tunnel. They dimmed, brightened, then dimmed again.

I recognised the pattern. I had watched the same thing all week when standby set two and standby set five tripped. Backup power was attempting to stabilise a load it could not support. The system was cycling, trying and failing.

A faint, wet scraping came from deeper in the tunnel, beyond the flickering lamps.

It drew closer.

Then it stopped.

The silence was absolute.

I did not move. Neither did Daniel. Maya slowly turned her head towards the sound but did not step back.

The scraping rushed forwards.

Something tall and thin moved into the red light. Its joints bent in the wrong directions, and there seemed to be too many of them. Its limbs were far too long.

I released Lewis and pulled one of my tool cases from my shoulder. I tore open the zip and dragged out a canister of fire-rated expanding foam left over from sealing cable penetrations. I ran to the blast door, shook the canister hard and sprayed the foam into the gaps around the pale organic obstruction.

It hissed and expanded, yellow and sharp-smelling.

Something struck the far side of the blast door. The whole frame shook.

Before the foam could set, a limb forced itself through the gap. It was pale and segmented, with joints that folded backwards.

Daniel fired three times.

I saw each impact. The holes closed.

They did not heal. They simply closed, as though the surrounding tissue flowed in to fill them.

I ran back to Lewis, who had slumped against the wall. His site pass was clipped to the chest strap of his body armour. I pulled it free, and he did not resist.

Looking up, I traced the overhead conduit until I found the emergency-lighting distribution box I had replaced five weeks earlier.

I opened the multi-tool from my pocket, selected the screwdriver and removed the panel cover in seconds. Inside was the main supply for the tunnel's emergency-lighting circuit.

Under ordinary conditions it ran from building power. Now it was being fed by the unstable backup system.

I pushed Lewis's site pass into the narrow gap between the breaker contact and its housing, using it as a shim to bypass the load limiter. Then I switched the breaker off and on again.

Every lamp in the tunnel surged to full brightness, far beyond its normal operating voltage. The dull red emergency glow became a fierce blue-white glare.

A high-pitched sound came from the other side of the blast door. It was not quite a scream.

The limb in the gap began to convulse. Its joints folded and straightened in rapid, uncontrolled movements.

Daniel caught it with both hands and forced it back through the opening. The expanding foam was half cured, sticky and dense. He shoved the limb beyond the door, and the foam swelled into the remaining gap.

The convulsions stopped.

The lights began to dim as the breaker tried to return the circuit to a safe load. I pulled Lewis's pass from the housing and pocketed it. The system stabilised.

Daniel looked at me. I looked back at him.

Lewis remained against the wall, breathing shallowly. Maya stood beside the coolant sampling room, watching the blast door.

'We need to move,' I said.

Daniel nodded.

We hauled Lewis upright again. Daniel took one side and I took the other. We started towards the stairs.

Maya did not follow.

I looked back. She was standing at the sampling-room door with one hand resting on the keypad.

'I'm staying,' she said.

'What?'

'If the foam fails, I can seal myself inside the sampling room and flood this entire section with coolant. Somebody has to remain here.'

'That's a bad idea.'

'It isn't optional. Containment is my job, and I'm the only person left who knows the system.'

Daniel adjusted Lewis's weight across his shoulder.

'The containment team will be here in thirty-five minutes.'

Maya nodded.

'That's fine. Thirty-five minutes is enough.'

She took out her pass and swiped it across the reader. The sampling-room door opened.

Maya stepped inside and turned back towards us.

'Seal the stairwell door behind you.'

Then the sampling-room door closed.

We carried Lewis up all thirty-two steps. By the second landing, my shoulders were burning. Daniel's breathing was controlled but heavy. Lewis made no sound at all.

We reached the ground-floor corridor and kept moving. The red emergency lamps remained on, and the operations office was still deserted.

We left through the same side entrance we had used before. The rubber wedge remained beneath the door. I kicked it free and let the door close behind us.

The car park was flooded with headlights.

Three vehicles had arrived, including marked CNC Mitsubishi Shoguns. Sirens were approaching in the distance. Armed personnel moved between the vehicles in dark police kit, their body armour deliberately unmarked.

Daniel stopped.

'Put Lewis down.'

We lowered Lewis onto the tarmac beside my Navara. Daniel knelt to check his pulse while I stepped back, trying to catch my breath.

Daniel suddenly slumped forwards.

There was no warning and no gradual collapse. He simply dropped.

I caught him by his body armour and eased him onto the ground.

'Daniel?'

He did not answer.

His pulse was steady but faint. I opened the front of his armour and found blood soaking through his uniform shirt below the ribs on his left side.

It was fresh.

I had not seen him being injured. I had no idea when it had happened.

'Medic!' I shouted.

One member of the containment detail turned and ran towards us. Two more followed. They took over immediately, and one of them pushed me back.

I moved aside and watched them work on Daniel. Lewis was conscious and speaking to another responder, although I could not hear what he said. Someone seized my arm.

I turned.

The officer wore dark armed-police kit with an unmarked plate carrier and a carbine slung across his chest. I recognised the scar cutting through his eyebrow.

It was Aaron Hughes, the same officer who had stopped me at the roadblock. Whatever the unmarked equipment was meant to conceal, he was now clearly part of a mixed Civil Nuclear Constabulary containment detail.

'Where do you think you're going?' he asked.

'Home. Whitehaven.'

'No, you're not. Name?'

'Callum Price.'

He took a notebook from his body armour and wrote it down. Then he held out his hand.

'Your site pass.'

I reached into my jacket and gave him my Sellafield contractor pass. He inspected it, then clipped it to his own armour.

'Wait beside the pickup.'

'Can I leave?'

'No. Have you got your keys?'

'Yes.'

'Give them to me.'

I handed them over.

Hughes opened the driver's door of the Navara and took Daniel's radio from the seat. He then locked the pickup and put my keys in his pocket.

I stood there as the sky began to lighten. It was not dawn yet, but a band of grey was spreading along the horizon.

The sirens grew louder. More vehicles entered the car park. Hughes spoke into his radio, and somebody replied, but I could not make out the words.

I sat on the kerb beside the Navara. One of the medics was still treating Daniel. Another team had transferred Lewis to a stretcher.

The armed personnel established a perimeter around the building. Portable floodlights came on, bleaching the colour from the red emergency lamps.

I waited.

About twenty minutes later, Hughes returned and ordered me into the rear of one of the Shoguns.

'Why?'

He did not answer.

I climbed into the back. The internal door handles had been disabled.

Hughes remained outside, speaking to somebody beyond my view.

The sun rose over the Cumbrian coast. I watched it through the locked vehicle's window.

I did not reach home that morning.