‘What the fuck is he doing in there?’ asked Lesley.

I rummaged in the stake-out bag and discovered that we’d eaten all the snacks except for Molly’s sandwich surprise, packed neatly in greaseproof paper. I gave them an experimental sniff.

‘Not tripe this time?’ asked Lesley.

‘Spam, I think,’ I said as I opened up the parcels and lifted the top slice of homemade bread. ‘My mistake,’ I said. ‘Spam, cheese and pickle.’

‘He’s coming out,’ said Lesley and raised the camera again.

Kevin emerged from the front door carrying a battered cardboard box. From the way he carried it I assumed it was heavy. This was confirmed when the van sank on its rear axle as he dumped the box in the back. He rested for a moment, panting, breath visible in the cold air, before returning to the house, where a minute or two later he reappeared with a second box and loaded that.

It’s a funny thing, but you only need to be following someone for a very short period of time before you start identifying with them. Watching Kevin stagger out the front door with a third heavy box I had to fight down the urge to jump out of the car and give him a hand. If nothing else, it would have speeded things up. As it was, we waited and watched him bring out two more boxes while taking the occasional picture to relieve the boredom.

Much too Lesley’s disgust I ate the spam, cheese and pickle sandwiches.

‘Are you planning to spend the rest of the day breathing out?’ she asked.

‘It’s an autonomic function,’ I said smugly.

‘Then open the window,’ she said.

‘Nah,’ I said. ‘It’s too cold. Tell you what, though.’ I fished out a Christmas-tree-shaped air freshener from the glove box and hung it from the rear-view mirror. ‘There you go.’

I was probably only saved from death, or at least serious injury, by the fact that Kevin chose that moment to get back into his van and drive away. We waited a couple of minutes to make a note of the house number and call AB for a pool check and then drove after him.

Kevin’s next stop was fifteen minutes away on the other side of the Westway in what had to be the last unconverted warehouse in the whole of West London. It still had its double-width wooden loading gates on which the original blue paint had faded to a scabby dark grey.

We drew up and watched as Kevin left his van, stamped over to the gates, unlocked the inset pedestrian door and stepped inside.

‘I’m bored of this,’ said Lesley. ‘Let’s go in and search the place.’

‘If we let him move on,’ I said. ‘We could have the place to ourselves, have a good look around before anyone finds out.’