So he did what any sensible chief constable would do in those circumstances and called his deputy with the details of who to liaise with at MI5. ‘We’ve got next to nothing to go on, so belt and braces. Firearms team fully bombed up. Maximum care – we don’t know who’s in there, what they’ve got and if they know how to use it. But keep the guys under control – I want no dead bodies we have to go to court over. Just get it done quickly and do not advertise. Use some tact and surprise for once.’

But the occupants of the garage had prepared for just such an eventuality. The blast blew the front roller door clean off and littered the street with shrapnel from the disintegrating breeze blocks. And by the time Tom and Woolf rolled up, forensics had found the remains of three men and, on the face of it, not much else but a charred mess.

‘Basically they had the place wired and ready,’ the Herts DI, who had taken charge of the site, explained mournfully.

A team in white coveralls were picking over the place with scrupulous attention. Even in this blackened, ruined state it was a potential treasure trove of information. There were several round plastic tubs about a foot deep, containing wholesale quantities of chapati flour and black pepper, along with plastic jerry-cans of hydrogen peroxide, every bomber’s hairdressing product of choice. Littered about the floor were a lot of triple-A batteries and the remains of several digital clocks and cheap mobile phones – all the components for homemade timers and detonators. And every one of these items, one of the team noted drily, was freely available on the high street.

But the premises wasn’t just used for bomb-making: there was evidence of makeshift sleeping quarters, with three camp beds and inflatable mattresses, a washing-machine and a clothes-airer hung with T-shirts.

Tom found Rafiq in less than triumphant mood. ‘Hey, you tracked it down. This is a direct connection to Zuabi. It changes everything. We’ll find out who these guys were and we’ve got their vehicle, so we can do retrospective number-plate recognition. You should be very proud.’

Rafiq looked pained. ‘After everything you went through in Texas, the least we could have done was not fuck this up.’

‘Bullshit. These guys had planned and prepared for this shit. If you’d gone in there you’d have been history. No amount of planning would have guaranteed against this going tits up. So don’t worry about it. You’re still alive, they aren’t – simple as that.’

One of the men in white chipped in: ‘And at least it’s over. The clock’s not ticking on this little bundle of fun. So we can take our time and make the most of what we’ve got here.’