Putting old or contaminated petrol in a car needn’t be catastrophic, but in the Golf’s case it was. With 37,000 miles on an 07 plate, it was a tight, solid little car before I accidentally wrecked it. Someone offered £300 for scrap, and I was about to sadly take it, when a pal pointed out that one second-hand Golf door alone costs £300 from a scrapyard. He urged me instead to buy a second-hand Golf engine for a few hundred quid and simply ‘drop it in’ — as he so persuasively put it. He even found a buyer for a Golf thus renovated who was guaranteeing trade price sight unseen.

I’m no mechanic. So I made a few calls and found Roy. Roy was available and he had enough confidence in his abilities to set a price for the job that seemed as unbelievably low as the trade dealer’s offer was high. Ordering a used 07 Golf engine from a nationwide scrap dealers’ website was as straightforward as ordering Michel Houellebecq’s latest from Amazon Prime. Roy and I set the day (Saturday) and the hour (10 o’clock) for him to come and do the work.

On Saturday morning, Roy’s white Berlingo van swung punctually into the drive. He got out and went straight to work, like a worker ant emerging from the egg. There in the garage was the engine sitting on a pallet. And there on the drive was the 07 Golf. He needed no further cues. Standing in my slippers and dressing-gown, cradling my kick-start coffee, I observed his purposefulness and confident expertise with unreserved admiration from an upstairs window.

Then I showered and dressed, made more coffee, and took a mug of it to him outside. His head was under the bonnet, buried deep in the engine vault. The cylinder head was off already and he was ratcheting away with his telescopic wrench. ‘Coffee, Roy?’ I said. He stood up, accepted his mug and took a grateful sip. ‘How’s it going?’ I said. ‘So far, so good. I might need a hand later to lift the new engine in,’ he said. He was in his mid-thirties and tall. The face was friendly and intelligent with a neat, thin beard arrangement. Vowels, modulation, diction and vocabulary were moulded by one of the middle classes.

He eyed me over the rim of his mug, placing me as I was placing him. ‘What do you do for a living?’ he said. I said that I was a sort of journalist, and this seemed to greatly excite his imagination. Quick-fire supplementary questions followed, such as how did an ordinary chap like me come to be one? And, which publications did I write for? I began to wish I’d said meat packer, which is what I usually say when the pointed question arises. Conversation tends to move on from meat packer (night shift) much more quickly. Now Roy began a ruthless examination of me as someone who is, or should be, ‘in the know’.

‘Islamic State,’ he said. ‘That’s Isis, right? You’re a journalist. What does Isis really stand for?’ I looked blank. Counting off the initials on his oily fingers, he said, ‘Israeli Secret Intelligence Service.’ I mimed an involuntary step backwards. ‘No really. It’s an Israeli organisation. The head of Isis is an Israeli. It’s well known. The creation of Isis is a brilliant plan by the Israelis to destabilise the Middle East. Didn’t you know?’ I promised Roy I’d google it.

But that wasn’t all. ‘And surely you must know,’ he said, ‘that the world is run by a small secret cabal concealed within, and largely comprised of, the executive of the European Union?’ I said, ‘You must think me terribly ignorant, Roy, but I’m afraid I didn’t. Anyone I might have heard of?’ Roy hesitated before divulging a name with a flourish, as if the mere mention of it would make the scales fall from my eyes. ‘John Major,’ he said. Quickly reforming my mental image of our former prime minister from gentle cricket lover to Master of the Universe, I said, ‘Well, no wonder he turned down that peerage, Roy.’ ‘Once you start to question things,’ said Roy, regarding me with a gnomic intensity, ‘everything falls into place. What do you know about the Jesuits, for example?’ I shook my head apologetically. And so for the next hour, with startling prolixity, but without pause, he told me the real history of the world, which seems to hinge above all on the ulterior motives of the Jesuits, the Knights Templar, the Knights of Malta, the European Union executive, and most obscurely of all on the mystical powers of the Stone of Scone. I couldn’t get a word in edgeways, even to excuse myself for a moment. But the Golf is now back to its former tight, nippy self. And, Sir John Major: we’re watching you.