Fortunately, my economics teacher at school never really shook himself properly after a trip to the urinals. This meant that instead of listening to his endless droning lectures on Smith and Keynes, I sat there, transfixed by the growing splotch of darkness on the front of his trousers.

This meant I was never tempted to leave school and get a dreary job in a bank. And better still, because I learnt about the importance of taking care while in the lavatory, I have never once been caught by the paparazzi with an embarrassing trouser stain.

What’s more, it means that, today, I do not concern myself with Dickensian theories and Victorian idealism when it comes to the question of business. I rely instead on common sense. For instance: if you have a product that people want to buy, you will do well. If it is too expensive, or ugly, then you will not. The end.

I have some sound theories on investment too. When times are good, put your savings in property, and when times are bad, put them in a high interest account at the bank.

Unfortunately, in the wake of Northern Rock, entrusting your money to the men in braces is more dangerous than using it to fund coups in Equatorial Guinea. And here’s the thing. It is impossible to predict which bank will fold next, which means it’s not safe to give your money to any of them. And because the police are too busy filling in health and safety forms to investigate burglaries, it is not safe to put it under the mattress either.

Gold has been the traditional recourse of the terminally scared but that’s expensive at the moment. So’s art. Someone recently paid £17m for painting of a fat jobcentre supervisor on a sofa so we aren’t really going to get much more than a Hallmark greetings card with our life savings.

Land’s a nono too. Clever people whose economics teachers did not routinely wet themselves have already noticed that just 8% of the world’s landmass is suitable for growing crops, and with the food crisis in full swing, much can be made from this.

So, farm land in Britain has gone from less than £2,000 an acre a couple of years ago to nearly £9,000 an acre today. By the time you have found someone willing to sell, you’re going to end up spending all your life savings on an allotment.

I have, therefore, been thinking about what can be done, and I’m delighted to say, the answer is very enjoyable. If we are about to enter a period of great economic turmoil with bankers hurling themselves out of the Empire State Building and stockbrokers selling their children for medical experiments, money will become worthless. So you may as well spend it now on things that will make you happy. A Fairline Targa 52, for instance. Or a villa adjacent to Lake Como. Or a nice car.

This, for once, really does bring me neatly to the semi-gullwing door of the Mercedes SLR McLaren Roadster.

I am more familiar than most with the original coupé version, having driven one nonstop - apart from a health and safety enforced break in Copenhagen (which wasn’t as long as the TV pictures suggested) - all the way from London to Oslo. It took 24 hours.

Apart from the woeful brakes, I liked it very much. Unlike most hypercars, this one was not built by an enthusiast, in a shed, on an industrial estate, and as a result it never gave even the tiniest hint that it was about to break down or disintegrate or explode.

It was also very, very fast. At one point, in Germany obviously, I hit 200mph. And there was more to come. This was, and remains, the fastest automatic car in the world.

And that brings me on to its strongest suit. Because the engine was at the front, and it had an auto box, and because the dashboard was pretty much the same as it is in all Mercs, you never felt overwhelmed by the simple experience of getting in and doing up the seatbelt. In a Koenigsegg or a Zonda, your heart is thrashing about in your ribcage like a coked-up and cornered dog before you’ve even started the engine. But because the SLR felt so normal, you were relaxed, which made it easier to exploit the immense power from that 5.5 litre supercharged V8.

Unfortunately, for McLaren anyway, the world’s super-rich heard what I had to say and promptly bought something else. Maybe because the McLaren race team outfits are so terrible or perhaps because the SLR didn’t capture the heart in the way that a Ferrari can. Who knows. But the SLR was not a sales success and as it failed to achieve its targets we now have the Roadster.

My God, it’s got presence. People suggest that if the devil were ever to pay us a visit, he’d have small horns and maybe some numbers in his barnet. But there is some evidence to suggest that he’s here now, with an SLR badge and no roof. And terrible, terrible brakes.

Other car makers have got carbon ceramic discs to work properly, but McLaren, which I think was the first to put them on a road car, has not. They operate like a switch, doing nothing at all when you first press the pedal and then smashing your nose into the steering wheel when you press it a bit more.

This is fine in a Formula One car when you never want to slow down “a bit”, but when parking, you do. And in the SLR McLaren, you can’t.

In time, you do get used to them, in the same way that you can get used to having no arms. And when you do, the rest of the car is a big slice of bonkers joy.

Some say that you can achieve much the same from a normal Mercedes SL. They say that the standard car comes with a folding metal roof, rather than a strip of canvas, and that it’s a third of the price and that it has more toys. But this is like saying: “Why buy a private jet when for so much less you could have a washing machine?”

The McMerc feels so much more exciting, so much more like a racer, albeit a heavy and enormous one. Lumber is not a word you normally associate with a car like this but that’s what it does. Lumber quickly. A Ferrari feels light and technical. A Koenigsegg feels like it isn’t finished. A Zonda feels like you’re on acid and you’ve fallen down some stairs. The SLR feels like Jonah Lomu. And the noise is extraordinary. No car sounds like this. It’s a big, dirty, bassy rumble. My daughter said it sounded like a big fart. She’s right. A massive, amplified fart from hell.

It is unique. Nothing else combines genuine blitzkrieg power with such everyday normality. Seriously. As you are carried by the Devil’s Wind, you have the leather seats, the sat nav and all the usual Mercedes bits and pieces. My only real gripe in this department is the roof, which is only partly electric. “That’s to save weight,” said the man from McLaren. Yeah, right.

I liked this car even more than I liked the coupé; but normally, of course, I would never dream of urging anyone to actually buy one. And not just because of the penny-pinching roof mechanism and the braking system. I wouldn’t recommend it because if I had £350,000 sitting about, I’d use it to buy a bond of some sort.

Now, though? Would you rather give your money to a banker so he can go bust with it or would you rather drive through the recession at 200mph in a big black Mercedes SLR McLaren?

The Clarksometer

ENGINE 5439cc, eight cylinders
POWER 617bhp @ 6500rpm
TORQUE 575lb ft @ 3250rpm
TRANSMISSION Five-speed auto
FUEL 14.5mpg (combined) CO2 348g/km
ACCELERATION 0-62mph: 3.8sec
TOP SPEED 207mph
PRICE £346,570
TAX BAND G (£400 for 12 months)
Clarkson’s Verdict Sell your house and buy this Mercedes SLR McLaren Roadster

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