Twelve months earlier, Silas set up a small intelligence unit to help identity criminals from Swindon’s vast database of CCTV footage. The town has more than six hundred local-authority-run cameras, making it one of the most surveilled places in Britain outside London. But the unit wasn’t about new software. It was about people, half a dozen ‘super recognisers’ – a mix of local police officers and one civilian, Kate – all of whom had been selected for their preternatural powers of facial recognition.

Kate’s results during the screening process were ‘off the scale’, according to the professor of psychology who had overseen her assessment. He’d never come across anyone like her. And much to Silas’s delight, Kate proceeded to identify dozens of criminals in her first six months, working off grainy images and mugshots as she watched hundreds of hours of CCTV. She also operated out in the field, identifying troublemakers in large football crowds, pickpockets in shopping centres. In retrospect, Silas should have seen that she was exhausted, but everyone was blinded by her results.

‘Why don’t we go to Kate, instead of trying to get her to come to us?’ Strover says. ‘She might be more interested in helping, given that this involves her.’

The same thought has crossed Silas’s mind. Kate would spot a match if there was one. Unlike this new software, Centaur, the lucrative contract for which was signed off a month after his unit was closed down. To be fair, it’s a long way off going live.

‘Our problem is the boss,’ he says. ‘Much as I’d like to go to Cornwall, the nail bars of Swindon are calling.’

‘Kate was in hospital for six weeks,’ Strover says quietly, glancing at her own nails. Silas notices a touch of sparkle. ‘If it was deliberate…’

Silas considers again whether Kate could have been targeted. It’s been troubling him ever since his meeting with Jake at the café. After the accident, he gave Jake and Kate reassurances that no one could be arrested and charged on the basis of one super-recogniser’s word alone. But there’s no denying that a particularly violent organised crime gang are now behind bars as a result of Kate’s initial idents. And he now knows that on the night of the accident she visited a county lines pub that might have links to the same gang.

He studies the still from the CCTV footage again. ‘I’ll go over to the Bluebell this afternoon, talk to the barman,’ he says, glancing at Strover’s screen. ‘What have you come up with?’

‘Looks like Kate’s living outside a village on the Roseland peninsula,’ she says. ‘South of Truro.’

Silas knows she’s living in Cornwall, but he has never tried to find out where.

‘According to Companies House, all her new partner’s businesses are registered at the same address down there,’ Strover continues. ‘Nothing’s listed in London.’