No, I thought, it still would have been flagged. Not least because DCI Seawoll was one of the most respected and formidable officers in the Met and you’d have to be remarkably stupid to try and do an end run around him.

I got out my torch and examined the tracker, which was identical in every way to mine and probably bought from the same online catalogue. Unless I wanted to open it up, it was about as traceable as a ballpoint pen. I took out my keys and scratched a tiny X into the casing in between the attachment magnets, took a deep breath to calm my nerves and strolled back towards Kevin Nolan’s crap Transit van.

I had to put it back where I found it but I couldn’t leave my tracker next to it, or whoever had planted the first tracker might find mine if they came to retrieve theirs. I couldn’t hear any voices as I reached the van. I hoped this meant they were all inside the lock-up. I bent down, replaced the tracker where I’d found it, removed mine and was just heading for the back of the van when the rear doors crashed open.

‘You need to clean this fucking van.’ It was Kevin’s probable brother. I froze, which was about the most stupidly suspicious-looking thing I could do, and the van rocked as someone climbed inside. ‘No wonder they’re not happy. Pass me the broom.’

‘It’s not the van,’ said Kevin from the back. ‘They think they should be getting more.’

‘They get what they pay for,’ said the voice. ‘I didn’t make the stupid deal.’

It’s always a risk when you have a plan that you fixate on it even when things go pear-shaped. I realised that because my plan had been to stick my tracker under the back of the van. I was actually waiting for Kevin and his friend to leave so I could do so – risking discovery the whole time. How stupid is that?

The van rocked rhythmically and I heard god-knows-what being swept out of the back. ‘I thought Franny’s was closed down,’ said Kevin.

I crouched down and put the tracker ahead of the front wheel arch and nonchalantly walked away. It wasn’t as good or secure a position as the back or the mid-section, but the magnets on those things are much better than they used to be.

We’d picked our position on the fourth floor of the car park with care. From there me and Lesley could have set up our camera with the telephoto lens on a tripod and had a direct line of sight on Nolan and Sons – had we only been willing to freeze to death or indeed had remembered to bring the tripod. The Asbo was conspicuously the only car in its row with the engine running.