This evening, he was sitting in the back of an unmarked, innocuous-looking Vauxhall Astra with burly, experienced PC Dave Horton at the wheel and Detective Inspector Paul Davey in the passenger seat, cruising the dark streets of Camberwell in South London, during another of their regular blitzes. Hunting anyone who might be carrying a knife or drugs, as well as moped gangs who were currently plaguing the city, snatching bags and phones.

The car’s interior had the familiar rank smell of most operational vehicles, of junk food and the odour of unwashed villains, but he didn’t mind. He peered out of the window, studying the body language of everyone they passed, while Davey watched the ANPR camera mounted on the dash, which would pick up the registration plates of any car with a previous history of association with any criminal activity.

All three of them were wearing jeans and T-shirts and bulky stab vests beneath bomber jackets, with brand-new, expensive trainers, issued by the Met. Fresh kicks were the principal status symbols of the new wave of young street criminals, and the easiest way for them to spot a copper was by the old and shoddy trainers they usually wore. Not any more. This had been one of Grace’s first initiatives since taking on his new role, to spend a tiny portion of the £15 million budget the Task Force had been given on kitting out his team with the latest drop of trainers.

They were travelling along a main road lined with shoddy shops and restaurants on both sides. As Grace watched a dodgy-looking group of youths on the far side, some in trainers, some in their casual, insouciant street footwear of sliders and black socks, Dave Horton suddenly shouted out, ‘Him!’ and swung sharply left into a side road, unclipping his belt and stamping on the brakes. As the car squealed to a halt, all three opened their doors and jumped out.

Grace sprinted after Horton and Davey, back onto the main road, just in time to see someone in a Scream mask, puffa jacket, gloves and trainers pedalling a bike hard along the pavement towards them.

Shouting, ‘Police!’ Paul Davey put his hands out wide to stop the cyclist, while Horton side-stepped into the road to stop the bike swerving past. Roy Grace braced himself to grab the rider if the other two failed.

The cyclist halted as the Inspector held up his warrant card. An aggressive youth in his late teens raised his horror mask and glared at the three men. ‘Yeah? What you want? You stopped me just because I’m black, right?’

Before either of the other officers could say anything, Roy Grace stepped forward, holding up his own warrant card. ‘So, we’re psychics, are we?’

‘What?’

‘Are you telling us we’re psychics?’

‘Ain’t telling you nothing. You stopped me because I’m black. That’s what you do.’

‘What’s your name?’ Grace asked him, pleasantly.

‘Darius.’