The wooden lintel was sagging, and I ducked to go under it. Inside, the darkness was so intense that I had to use my pencil torch. The beam picked out an old wooden partition of horizontal planks, extending half-way out across the stable. Beyond it the earth floor was covered with rough, half-rotten hay. Raking some aside with my fingers, I felt iron: the shaft cover. Quickly I cleared debris away from two padlocks – the two we’d been shown in the photo, which were not rusty but coated in dust. Clearly it was some time since they’d been touched.

‘Stay in the doorway,’ I breathed at Pavarotti, and he faced outwards, on guard, as Toad went to work, opening the barrels of the locks with his levers. I held my torch-beam steady on his hands, wincing at every little click and scrape.

The first lock gave itself up easily after no more than a couple of minutes, but the second was more stubborn. As Toad fiddled and shook, Pay let out a sudden hiss over his shoulder. Instantly I doused my torch. Peering past our sentry, through the doorway, I saw two women come out of the church and walk towards the big building.

We let them get clear, then started again. At last there was a louder click, and the hasp of the second lock fell back. As I carefully lifted the cover its two hinges groaned. My torch, pointing straight down, lit up a square shaft with brick walls, and I could see at a glance that it was big enough to take the component parts of Apple. To make certain, I’d brought with me a piece of string thirty inches long – the maximum dimension we needed – and when I stretched it out from one edge it ended nearly a foot short of the other. That was one problem solved.

The disappointment was the ladder – or rather the lack of one. Instead of a succession of built-in steel rungs there were only two, a foot apart, close to the top of the shaft. From the holes and pits in the brickwork lower down, it looked as though the rest had been ripped out.

‘We need the ladder,’ I whispered.

I unrolled the springy bundle from my bergen and made one end fast round both hinges. Then I pulled on my overalls, and I heard Pavarotti rustling as he too kitted up.

‘All set?’ I asked.

‘Fine.’

‘Right, then, Toad. We’ll see you in half an hour.’

I lowered my legs into the shaft and eased my weight down the wire rungs, feeling for them with one foot after the other. Fourteen changes of grip, and my feet touched bottom. As soon as I stepped off the ladder it went slack. I knew they’d feel the change up top, and that Pav would start down.