I’ve been in a 1950s Russian plane that had spent most of its life with the Angolan air force before some hopeless Cuban drug addict in a soiled baseball cap flew it, and me, into one of the most savage tropical thunderstorms the world has ever seen.

I’ve also raced a drag snowmobile, rolled an F-15 fighter, spun a Koenigsegg and been in a helicopter gunship, over Basra, when someone stepped into his garden 500ft below and fired a heat-seeking missile at it. So I understand the concept of fear.

But there is nothing quite so buttock-clenchingly terrifying as the moment when David Dimbleby turns to you on Question Time and asks for your opinion on something about which you know absolutely nothing.

There you are, in front of an audience, with the television cameras rolling, and you have to summon up a cohesive thought, immediately. You can’t joke because jokes aren’t allowed in the serious world of political debate. You can’t mumble. You can’t even look at your shoes and, in the best traditions of the school bad boy, mumble: “Don’t know, sir.”

The best person I ever saw on the panel was Enoch Powell. When asked for his thoughts on, oh I can’t remember what it was now, some frightfully important issue that mattered then but doesn’t now – homophobia in the fishing industry, probably – he didn’t bluster and talk about how he has an understanding of the trawlerman’s way of life because he once spent a lovely holiday in Lowestoft, which is the sort of thing Patricia Hewitt or Margaret Beckett might do.

He didn’t thump his tub either, making platitudinous noises to whip up a frenzy of applause. He said simply: “I have no knowledge of this subject.”

I was reminded of old Enoch’s honesty last year when I telephoned a chap at Mercedes-Benz and asked if I could borrow a quasi-racing, hard-topped version of the AMG SLK. It was called the Black and it all sounded very exciting.

Now, there are a number of excuses the public relations executive can use when he doesn’t want to lend a demonstrator to someone. He can say, “It’s been crashed”. Or, “It’s being used by the motoring correspondent of the Welsh Pig Breeders’ Gazette at the moment”. Or he can say, “I’ll get back to you on that” and not do so.

But the chap at Mercedes said straight away: “Ooh, the SLK Black. No. I don’t think you’d like it very much.” And put the phone down.

This means, of course, that when he rang the other day and offered me a drive in the Black edition of the CLK, I figured that since he was such an honest chap, I was going to like it. The thing is, though, I had absolutely no idea how much.

The standard CLK is not the most exciting car in the Mercedes range. It sits in the mix like Peter sits in the Fonda family. Or that other bloke who wasn’t Paul Weller and Bruce Foxton in the Jam.

It’s based on the old C-class saloon, which means it’s not as nice to drive as the current C-class saloon. And to make it even less appealing, it has fewer doors, less space inside and is considerably more expensive. This wouldn’t be so bad if it were a looker, but it’s a bit like the girl next door’s plump sister.

On paper, the Black looks like even more of a cockup. Because they’ve removed most of the luxury trimmings and the rear seats found in the normal 63 AMG version, and this has somehow made the car heavier. And then they’ve added a whopping £34,000 to the standard car’s already eyewatering list price of £66,000.

So, the car you are looking at in the pictures this morning is priced to take on a Ferrari F430 and the Porsche Turbo. I know, I know. It sounds like a German idea of a joke. But I promise you this: it is not a joke at all. Like everything to come out of the Fatherland since it was formed in 1871, it is utterly and deadly serious.

The reason why this car has gained weight over the standard version, despite the absence of electric seats and sat nav and so on, is because, underneath, it has been radically altered with a chunky limited slip differential, a new wider axle and lots of other Brunelian strengthening beams.

They’ve had a fiddle under the bonnet, too, completely redesigning the intake and exhaust systems and fitting a new management system so that now, the 6.2 litre V8 churns out a thunderous 507bhp. Couple this to the beefed-up undersides and the results are remarkable.

Imagine drinking a pint of hemlock, setting yourself on fire and then jumping out of a plane when it’s directly overhead a combine harvester. You don’t know what’s going to kill you: only that you are going through the Pearly Gates at great speed very soon.

That’s what the Black feels like. Exciting beyond words. Terrifyingly exciting. White-knuckle, eyes-on-stalks, sweaty-armpit and tensed-buttocks exciting. David Dimbleby exciting.

Initially, you don’t drive this car: you just cling on for dear life. For the first few miles, I genuinely thought it was actively trying to kill me. But then I became used to the way the back skips and settles and started to enjoy it. Then the enjoyment turned into sheer, unparalleled joy. Then I started to think that I might have actually wet myself a bit.

It does not drive like any other car, this one. It doesn’t feel planted like a Porsche Turbo, or alive, like a Ferrari 430. It feels skittish, as though it’s balancing all the time on a knife edge; that razor-thin sliver that separates absolute joy from certain death.

And what makes it all the more extraordinary is that you don’t feel like you’re in a hunkered-down racer. You have an automatic gearbox. You have a hands-free telephone, and air-conditioning, and a ride that is not exactly soft. But it’s not killer hard either.

It’s the same story with the noise. When you accelerate, it sounds much like I imagine a burning dinosaur might sound. But on the motorway, you can still hear Terry Wogan, even when he is muttering.

Sadly, all is not sweetness and light. The front bucket seats are stunning but only Jon Bon Jovi has snaky enough hips to sit in them, and do the seatbelt up. And then there’s the back. Because the rear seats have been taken out, you end up with half a square mile of carpeted but inaccessible uselessness.

Technically, it’s possible to put them back in again – and it’s not like the extra weight will make much of a dint on an engine that produces more than 460 torques – but sadly the European Union rule makers say that’s not allowed because it would cause the rear axle to snap, and the headlamps to point at Mars.

And then there’s the styling. All those Mr Universe bulges are absolutely necessary to shroud the wider axles, and cool the carbon brakes. I know this. And I don’t doubt it would look great at Silverstone. But would it look right on a wet Wednesday in Tamworth? Or would you just look like the most terrible show-off?

You might think, then, that if it’s a look-at-me head turner, you may as well go the whole hog and buy a Ferrari instead.

I’m not so sure. Quite apart from the fact that the Merc is likely to be more reliable and comes with a proper boot, and all the iPod ’n’ sat nav tinsel that you really need these days, the simple fact of the matter is this: for sheer excitement, the CLK Black is a match for the 430.

For sheer excitement, the CLK Black is a match for absolutely anything. Since it went back to Mercedes, I have been thinking about it a lot. Because I’m not sure that anyone’s life is quite complete unless they have one.

Vital statistics

Model Mercedes-Benz CLK Black Series

Engine 6208cc, eight cylinders

Power 507bhp @ 6800rpm

Torque 465 lb ft @ 5250rpm

Transmission Seven-speed automatic

Fuel 18.5mpg (combined cycle)

CO2 369g/km

Acceleration 0-60mph: 4.3sec

Top speed 186mph

Price £99,517

Road tax band G (£300 for 12 months)

On sale Now

Rating

Verdict Truly monstrous (but in a good way)

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