‘On Abu Mujahid, our best lead is still the missing hour when his van went off the radar in London two weeks ago. He was either visiting his base, or storing some, or all, of the weapons he’d picked up earlier that day in Burgess Hill. Either way, we need CCTV of him during that hour. DI Bose’s team has ploughed through CCTV footage cameras across the black hole with no success yet. I want more resources on that search.

‘And his van is somewhere. It may be in a lock-up, it may be on the streets with new plates. I want every grey Ford Transit in a public space checked and double-checked.

‘So far he’s not approached his family or any known associates. We’ve had them under surveillance, but it’s time to bring them in and squeeze them dry. Now, on to possible targets.’

A map of London, with three red circles, appeared on the screen.

‘We’ve narrowed it down to three,’ said Gabriel. ‘All involve large crowds, all outside, and with potentially high impact. The marathon, the England match at Wembley, and the Pride march in East London.’

Tennant signalled with a finger to the MI5 case officer sat opposite.

‘I think we can help on that,’ she said. ‘As you know, the GID has been increasing its propaganda online over the last couple of months and we’ve been running a content-analysis study. We’ve found a disproportionate emphasis on Western hedonism compared to similar propaganda from similar ISIS splinter groups. The GID are pushing hard on Western sexual immorality and, in particular, homosexuality. It’s a significant difference which is likely to reflect nothing more than the personal bugbear of the GID leader Mohammed Huzaifa. But if this attack by Abu Mujahid is designed by Huzaifa to put the GID on the map and serve as a declaration of intent, it’s plausible that they would target Pride. There is no clear intel, but that is our best judgement.’

‘I think it’s got to be Pride, ma’am,’ said Skeffington.

That was quick off the mark, thought Gabriel. Is he trying to impress Tennant?

He continued: ‘Not just for the ideological reasons, ma’am. It’ll be chaos down there and our officers will be hard-pressed to monitor the crowd. Abu Mujahid could get a drone over the crowd without anyone spotting it or hearing it over the din.’

Tennant sat back, scratching his armpit. ‘I tend to side with our colleague from MI5 here too. Pride is outdoors, it’s vulnerable, it’s contrary to conservative Islamic teaching. GID want impact, but they also want to reduce the risk of a backlash from their potential supporters overseas.’

Gabriel hated to do this in front of junior officers, but there was no time for protocols today.

‘I’m sorry, sir, but I disagree. I know Abu Mujahid. He’ll want something spectacular, in front of the world. The Wembley match is going to be on live TV. The impact is far greater. Can you imagine a drone exploding above the spectators?