Her thoughts returned to Fletcher’s missing technology. He must have a phone, or a laptop, or a tablet, and he had taken care to hide it. The flat was the obvious hiding place, but maybe there was something here at the theme park that forensics had overlooked.

#

Back at the Notorious ride, SOCOs were still at work, swabbing victims, fingerprinting the carriages and photographing every square inch of the platform, stalls and track. It could be hours before they finished and the victims finally taken away for post-mortems in Central London. Gabriel pulled on her sterile forensic suit and gloves, crossed the scene-of-crime tape and strolled briskly to the cabin on the station where Fletcher’s colleague Lisa had been working.

The cabin was little more than a fibreglass box with two windows, a wall-mounted electric heater, a desk and chair, and lingering body odour. The floor appeared solid and was covered with stained yellow linoleum. Gabriel put down her bag and gave the corner of the flooring a tug, but it stayed put.

What about the ceiling? She pressed gently upwards on a polystyrene tile and it moved. She pushed again and slid it to one side, wincing at the squeak of polystyrene against polystyrene.

‘Pass me the chair, Jorell.’ Campbell yanked the plastic chair from behind the table, allowing Gabriel to step onto the seat and gingerly poke her head through the gap in the ceiling.

‘Jorell – turn on the torch on your phone and hand it over.’ Her voice was muffled inside the cavity.

She felt the phone being pushed into the palm of her hand. She squeezed it through the gap alongside her head and held it out. The glare of the blue-white light made her blink as it revealed a shallow space of dust, cobwebs and there, just out of reach, a biscuit tin.

‘Got something,’ Gabriel said, reaching further in, her heart beating faster. She flicked the tin carefully towards her and stepped off the chair, placing the metal box on the table. She prised off the lid with a fingernail, breaking it on the way, and exposed a stash of papers. She recognised most of the sources. There were printouts from Flashlight, a neo-Nazi Danish site beloved by British fascists. At the bottom was a piece of ancient history – a grubby copy of Spearhead, a far-right magazine from the 1980s.

Gabriel clambered back onto the chair and poked her head through the gap once more, this time facing the other direction. Half an inch from her probing fingertips was a small plastic bag. She raised herself on her tiptoes, gripped a corner and pulled it towards her face. She dropped it on the table alongside the biscuit tin and stepped down.

Gabriel could feel Campbell’s breath on her cheek as he leant forward to watch her slide a mobile phone from the bag. Gabriel stared. It was an expensive model, from the last year, and not the sort usually used as a burner – the pay-as-you-go phones bought over the counter, hard to trace and popular with drug dealers, organised criminals and terrorists.