The cabin seemed suddenly claustrophobic and Gabriel felt the urge for fresh air. She stood outside on the platform, deep in thought.

‘Ma’am.’ Campbell interrupted her. He was holding out his own phone. ‘Think you need to see this.’

He handed it over. The screen was playing a YouTube video, posted online minutes earlier, and she immediately recognised the puffy face and greasy hair of Gareth Fletcher. He was stood in a shabby sitting room, in front of a Union Jack, a swastika and a poster of what looked like a trident symbol. A line of letters was scrawled on a sheet of paper above his head – Gabriel could make out the first two, RA, but the rest were unclear. Over them, someone had scribbled the numbers 14 and 18. Fletcher’s white vest revealed a tangle of tattoos on both arms. On his left shoulder, Gabriel could make out 88 in a gothic font. Gabriel was well aware of the obsession on the extreme right wing with numbers and codes, but this seemed excessive, even for a neo-Nazi.

He spoke quickly, too quickly for Gabriel to catch all the words on her phone’s speaker. It was rambling, nervous stuff, blaming the Muslims, blaming the Jews, blaming the blacks, blaming the gays. The editing was rough too – there were obvious cuts and missing words. She watched with a professional’s detached interest until the last line, when she nearly dropped the phone.

‘…and I do this today in the name of the National Resistance Force, in the name of history. Fourteen words. We must secure the existence of our people and a future for white children.’

The NRF? Gabriel’s immediate instinct was disbelief. The NRF was a crackpot group, outlawed a year or two earlier, but not regarded as a serious threat. She was suddenly aware that Campbell was staring, waiting for her reaction. If this was right – and the phone hidden in the ceiling above them and Fletcher’s furtive preparations for this attack suggested it was right – then Fletcher’s claim he was making history was no exaggeration. This bloody mess was the first attack of its kind by an organised extreme right-wing group on British soil.

But there was something more.

‘Campbell, does anything strike you about this video?’

Campbell shook his head. ‘Usual XRW stuff, ma’am.’

‘Look again.’ She handed over the phone. ‘Look at the flags, the posters, the way he’s stood. Doesn’t it remind you of anything?’

Again, Campbell shook his head.

Gabriel looked at her watch. Tennant would be heading to Downing Street by now for the pre-COBRA meet. Technically, she should be contacting her direct boss, the commander. But sod it. And again, she felt the glow of an errant schoolchild as Tennant answered.

‘Of course, just because Fletcher claims he was with the NRF, doesn’t mean he was,’ Gabriel said, almost hopefully, after she filled him in. He had seen the video just moments before.

‘No, but what you’ve found is hugely indicative. And no electronics at his home?’