The video fast-forwarded. Again, Abu Mujahid arrived on foot, collected a box and left.

‘Is that it?’ said Skeffington, disappointed.

‘Yep,’ said the manager.

‘We’re going to need to get a team in that locker with sniffer dogs,’ said Skeffington. ‘In the meantime – Sergeant Campbell, call HQ.’

#

CTOC, St Pancras, London

‘And you’re sure he was walking?’ said Gabriel.

‘Yes, ma’am,’ came Campbell’s voice. ‘He arrived on foot twice. Each time he was in the unit about four minutes.’

‘Hang on, Jorell.’ She put her hand over the phone. ‘Eva – get a look at CCTV from West Link Road, yesterday around 10.10 and 11.00.’ She took her hand away from the phone. ‘Jorell, the timing here is significant. If he was walking the entire time, then he was carrying this stuff – which we assume are explosives and weapons – to a location within twenty minutes. A safe house? A flat? A vehicle?’

‘Why walk? Why not drive?’ said Campbell.

‘ANPR?’ said Gabriel. ‘Maybe he wanted to keep off the radar. Maybe he doesn’t like buses? He’ll have had a reason. But what was in the locker? Have forensic swabbed?’

‘Yes. Waiting for results. But the dog team picked up traces of explosives. The handler is pretty confident and I have got EOD on their way with their kit to double-check.’

Explosive Ordnance Disposal would be able to generate an immediate result.

‘That’s our answer,’ said Gabriel. ‘He’s collected the explosives and rifles from Burgess Hill then dropped them off at the storage unit. Or the explosives at least. And then he picked them up yesterday.’ There was a moment’s silence. ‘Yes, Eva?’

Bose had appeared, flushed and breathless.

‘Got the CCTV of West Link Road and, yes, he was walking, ma’am – both times with a rucksack,’ she said. ‘He vanishes soon after, no sign of a car.’

‘Right – get a map up on the screen. We can start to narrow down the location of his destination. Campbell, stay up there for the moment. It’s likely you’re near the cell. I’ll send armed response up there immediately.’

#

Tennant looked at the map on the video conference screen. ‘What if he wasn’t walking there and back?’ he said. ‘Who’s to say he didn’t use a vehicle?’

Gabriel shook her head. ‘Don’t think so, sir. He arrives at the storage unit at 10.14 and leaves four minutes later with rucksack laden with God knows what. He’s back at the depot with an empty rucksack at 11.02. That means he was away for forty-four minutes. We can assume he will have taken a few minutes to get into his house, or warehouse, or shed, or whatever hole he’s using as his base, unpack the explosives and stash them safely, and then come out. Let’s assume that’s taken him four or five minutes. So that leaves him twenty minutes to get to his destination, and another twenty to get back. We know he walked into the depot and walked out – there’s no sign of a car or van. Explosive Ordnance Disposal have confirmed that there were explosives in the storage locker and I can’t accept that he’d have risked hopping on a bus.’