I simply do not know how those F1 boys get round the first lap at all. And, what’s more, I don’t really have much of a clue about how they do the second, either.

Because, having slithered and spun round the first lap, you slow right down because you simply don’t trust the tyres to work. And that means they don’t get hot.

It’s catch-22. Go fast enough to warm them up and you spin. Go slow and you have to play the snail until the chequered flag comes down. After several laps, however, of eyebrow-matting concentration, I hit a pigeon. Which was a bit uncomfortable. For it.

Stopping was no easier. Brake at what you think is the right place and you will stop dead about 400 yards before the corner. A car this light has no real mass and, consequently, stops with a panache no road car can match. So you start to get cocky, braking later and later until, eventually, you will lock the fronts. When this happens in a normal car on normal tyres, there is much wailing and screeching. But in the single-seater, on slicks, there is no noise at all. For a while, you sit there, thinking all is well. Then you notice the smoke, and then you realise that you are heading straight for the pit wall at about a million.

Over the years, I have driven many cars, some of them very fast. And in my mind this had prepared me for life in a proper racing car on proper racing tyres on a proper racing track. It hadn’t, though. It’s like spending your life hiring out donkeys on a beach and then imagining you could win the Grand National.

And then there’s the question of g. F1 racing drivers talk about how they suffer from the effects of this, and I always feel compelled to drive to their houses and punch them in the face. Because the g they are talking about is lateral. And lateral g is for nancy boys.

In essence, the effects of g are felt in the form of blood moving around inside your body. In a fighter plane it moves up to your head in times of negative g — which makes you feel light-headed and sick — and down in times of positive g, which causes you to lose your peripheral vision and then die.

In a racing car it can move only laterally — from side to side. So it’s not all in your head or all in your feet. It just sloshes from shoulder to shoulder. Which is no big deal ... I’ve always thought.

You see, eventually I did start to push the single-seater, and it was a revelation. Because you can see the front tyres and because they have so much grip when they are warm, you can place the car precisely where you want it to be at speeds you would imagine were simply impossible. All these years, I’ve scoffed at racing drivers for dismissing all road cars as rubbish, but I began to see their point. I may have even whooped occasionally like an American. And then my neck started to hurt. And then the muscles in it turned to fat. And then, after a couple of laps, I couldn’t hold my head up at all. When I got out of the car, it looked as though I’d been hanged. Lateral g, then, is unpleasant.

Which brings me to the BMW Z4. To a racing driver, who is used to slick tyres and fish-sharp reflexes, it’s wallowy and slithery and horrid. But to me it’s brilliant. Mostly because you can drive for more than 10 minutes without your head coming off.

I also liked the styling, the ride — provided you stay out of the sport settings — the engine’s urgency, the fluidity of the responses and the elegance of the interior. Though, that said, this is not a car you can drive in cuff links. Because the centre console is set up for left-hand drive, every time you change gear your silver dog turd, or whatever, will hit the iDrive knob, which in extreme circumstances can cause the cabin to be filled with rap noises.

However, I’ve thought quite hard about this and can confidently say that the Z4, with its folding metal roof and softer feel, is now the best of the medium-sized sports cars. Certainly, I prefer it to the Boxster and the Mercedes SLK.

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