Bose’s team had been trawling for three days for his van. First, they had searched through video collected by three local authorities, as well as the cameras owned by Transport for London at Tube stations, railway stations and bus stops.

The team had started by tracking Abu Mujahid’s route from the point his van – freshly laden with whatever weapons, ammo and explosives he’d picked up in Burgess Hill – was last seen, driving through a bustling junction in Hammersmith at the start of his missing hour a week last Friday.

The next local authority CCTV camera on that road was a quarter of a mile further on, and a trawl of the footage had shown he hadn’t gone that way. That meant he had turned off the main road. So then the team began the careful screening of CCTV camera footage of all the side roads he might have taken. And the side roads that led off those.

It quickly became clear that the team needed more coverage than the local councils and Transport for London could offer. Officers had been sent out on foot to trace the route, find shops, petrol stations and offices whose cameras covered the road, and grab the footage to send back to HQ.

The team had then viewed hundreds and hundreds of hours of those camera feeds over the missing hour, replaying each video twice, looking for Abu Mujahid’s grey van. Even when they ran the videos at high speed, it had taken twenty officers and civilians forty staff-hours so far. It was a mammoth, tedious job. And so far, there had been no sign of the elusive van.

#

‘Ma’am, sir, I’ve got the details of Abu Mujahid’s order.’ Campbell jogged over to Skeffington and Gabriel. ‘And you were right, ma’am. Amazon confirmed they were delivered to a newsagent in Kendal on Friday evening – a week ago – and were picked up on Saturday at 9am. The timing of the collection matches Abu Mujahid driving in and out of Kendal.’

Gabriel snatched at the sheet.

Campbell continued: ‘Abu Mujahid made the order under a false name – H. Townsend – using Amazon gift cards he bought or stole. He probably used an internet cafe to place the order and he had them delivered to a newsagent in Kendal.’

‘What did he order?’ said Gabriel.

‘Two drones,’ said Campbell. ‘Worth about five hundred pounds each – not top of the range but not kids’ toys either.’

Drones? That wasn’t what Gabriel had been expecting. Chemicals, perhaps, or fertiliser, or something to make a bomb.

‘What does he want drones for? For snooping?’ said Skeffington, mirroring Gabriel’s train of thought.

‘Maybe, maybe,’ said Gabriel. ‘Okay, guys, get the whole team together in ten minutes. This changes everything. I want to know our options and the potential targets. Pull together a list of possible targets for a drone attack.’

#

Tennant walked into the conference room as Campbell was mid-sentence. He gave an almost imperceptible nod for the DS to continue as he slumped into his seat.