My boy was downstairs cooking Sunday roast. Earlier, I had been clambering about on a woodpile, stepped awkwardly, and twisted my knee. So I was upstairs lying on my bed stinking of Deep Heat. Then my grandson appeared in the doorway to report that lunch would be ready in an hour. I held out my arms to him. The lad dutifully removed his shoes and came and lay next to me. I cuddled him passionately until he’d had enough of it, then I reached for the iPad and asked him what he would like to watch on YouTube.

‘Car crashes,’ he said. Apart from making Batman attack vehicles out of Lego, watching car crash compilations on the iPad is our current favourite pastime. It’s better than coke. The best of the compilations are Russian. My goodness there are some lunatics on the road over there. Driving in Russia is so dangerous that for legal and insurance purposes every car has a permanently switched on webcam fixed on the road ahead. And some enterprising persons have strung together the best of the best smashes and posted them online.

We lie on our backs. He rests his head against mine. I hold the tablet about nine inches in front of our faces. United in the intensity of our imaginations, we look through the screen as though it is our car windscreen and we are actually driving. Each clip lasts about 30 seconds. We might be driving, for example, along a two-lane expressway, in the right-hand lane, in a line of traffic travelling a steady 40 mph. The landscape is flat, the road is dry, the sun is shining. There is usually a soundtrack. Russian pop music is playing soporifically on the car radio and there is an occasional swish of a car going by in the opposite direction. What can possibly go wrong?

Well, in Russia, at any moment, there might be a 60ft articulated lorry suddenly sliding towards you at 60 mph — on its side. Or some reckless lunatic will come screaming past at 100 mph in a doomed attempt to overtake the next ten cars, swerve to avoid a car coming in the opposite direction, and go bouncing, and then tumbling end over end, across the Steppe.

But what a nation of stoics! Our car might be clipped by some drunken Stirling Moss, veer off down an embankment, turn over three times in a ploughed field, come to rest upside-down, and all we will hear from the driver and passenger is some mild grumbling in Russian.

So we watched about 50 car crashes, one after the other, crying out in horror or making punched-in-the-stomach noises at the point of impact — it’s impossible to watch without involuntary exclamations — until we became sated, and finally bored, even with this exhilarating fare, and we went in search of a more potent fix.

Next we watched a succession of the most dramatic and terrible Pamplona bull runs we could find. In those taking place between the years 1997 and 2001, we tried to spot grandad (who went religiously every year at that time) among the thousands of runners. ‘There’s grandad!’ I lied, as a bull deftly removed a fallen runner’s trousers with a flick of a horn tip and then tried to kill him. Not daft, my grandson watched unperturbed, knowing the outcome couldn’t have been that serious if I was still alive and lying beside him, more or less in one piece.

And, most perceptively, he was far more interested in the role of the pastores (shepherds), the men in green shirts, armed with thin sticks, who drive the bulls forward along the narrow cobbled streets, whose unobtrusive but decisive presence is indicative of a certain amount of subtle supervision of the herd that one could so easily miss in the hubbub and general chaos. I ran at the Pamplona bull run several times before I noticed these chaps. After that, the running of the bulls became a slightly more innocuous affair than it had been previously.

I congratulated my grandson on going straight to the heart of the matter at a single glance, and while he was in such a perceptive frame of mind, I showed him his first bullfight. We saw the extraordinary one at Pamplona where the Miura bull Bombito was glued to the picador’s horse for seven minutes and the matadors resorted to the undignified method of trying (and failing) to pull him away by his tail. My grandson was mesmerised.

And then we were called down to Sunday lunch. Roast beef. As we seated ourselves among the rest of the family gathered around the table, we were asked what we had been doing so quietly up there for the last hour.

‘Watching YouTube videos,’ I said. Oh yes, they said. Which ones? ‘Postman Pat,’ I said, winking frantically at my grandson.