Now make like a stunned goldfish

The mothership has landed - and deposited a phenomenal beast of a car they call the McLaren Mercedes SLR. Sean O'Grady approaches with caution

One of the things the McLaren Mercedes SLR was never designed for is to be parked in an undistinguished suburban street in London. Or anywhere else outside Monaco or Beverly Hills, or Moscow, these days, I suppose. In its natural, plutocratic environments, places where conspicuous consumption is taken for granted, its outrageous presence would be hardly noticed.

One of the things the McLaren Mercedes SLR was never designed for is to be parked in an undistinguished suburban street in London. Or anywhere else outside Monaco or Beverly Hills, or Moscow, these days, I suppose. In its natural, plutocratic environments, places where conspicuous consumption is taken for granted, its outrageous presence would be hardly noticed.

In Ealing it is as if Martians have landed. This must have something to do with the semi gullwing doors and the Batmobile styling, I guess, and the grumbling, dragsterish sort of sounds the SLR's V8 5.4 litre supercharged engine emits. Among others, a group of ten-year-old girls gather round the car. One asks: "Does it cost a lot of money?" "Yes. Lots and lots of money. Guess how much." She pauses to think for a moment about the largest fortune she can conceive of and then, almost too afraid to utter the awesome words, she whispers to me her guesstimate of the list price of an SLR: "Six... thousand... pounds."

Well, she's only about £300,000 off the target, and more in the Kia Picanto ball park, but six grand is six grand and, as a matter of fact, still a lot of money to me, too. So rather than fry her young mind with the realities of modern consumerism by informing her that it'd be about enough to buy one of the SLR's magnificent turbine-style alloy wheels, I tell her that she's got it about right and to start saving up. I can't be too smug, though. For I know that my current new car budget is about £6,000.

The price of this extraordinary piece of machinery (£313,465 to be precise) is one of the two key numbers you need to know if you drive one, because you are invariably asked wherever you go "how much?" and "how fast?" "How much?" we have covered. "How fast" is 206 miles per hour. If you want more figures, I have them. According to Autocar, who tested exactly the same SLR as I drove, and have the wherewithal to measure these things legally, the McLaren Mercedes will take you from rest to 30 mph in 1.8 seconds, to 100 mph in 7.6 seconds and on to the magic 200 mph in not much more than half a minute. Or about the time it took you to read that last sentence.

That's what you can do with 626 bhp at your disposal in a car made from high strength and low weight carbon fibre. For the purposes of comparison, a mid-range Ford Mondeo delivers about 145 bhp, a BMW Z4 has 231 bhp and a Rolls-Royce Phantom 453 bhp. The SLR is one of a new breed of supercar - the Porsche Carrera GT and the Ferrari Enzo are others so far - seemingly built with the purpose of testing the laws of physics. Just how much power can be put onto a road via a set of wheels? I look forward to seeing how Volkswagen tame their forthcoming Bugatti Veyron's boasted 1,001 bhp.

For me, punting the SLR around Betjeman's Metroland and the M4 left me with the abiding sensation of having ridden a tiger. You flick the little lid on the gear lever and press the red illuminated starter switch. It growls. You move off. The SLR is twitchy, always looking for signs of hesitation, always threatening to break away. Learning how to control it, I had to treat the car with maximum respect. As with the Noble M12 I drove earlier this summer, I knew I was in the company of something that was beyond my capabilities.

You dip into the SLR's race bred potential rather than gorge yourself on it. You do not, if you are in your right mind, "floor it". Approach the beast with caution and you are rewarded with brisk, fuss-free progress when you need it; 50mph to 70mph in 1.4 seconds for example. I even managed to drive it safely with the electronic stability control turned off. So I didn't feel the SLR was entirely wasted on me, but there was an element of the thoroughbred Arabian stallion taking kids for a ride on Blackpool pleasure beach about a punter like me driving such a masterpiece.

Or maybe not. Unless you own your own racetrack (and I admit a few SLR owners probably do fall into that category) you won't be able to tear the backside off it on a day-to-day basis. I notice that the chaps over at Top Gear magazine managed to set the SLR's ventilated ceramic brakes on fire during their time with it. Hooligans, I say.

As the Mercedes press office were keen to stress, the SLR is very much your usable sort of supercar, sir, as easy to drive as a C-class saloon. It may only have two seats, but it has a surprisingly large boot. It has an automatic gearbox (with a tiptronic option if you want to get frisky). It has a radio/CD player, with handy control buttons on the steering wheel and it is fitted with perfectly weighted power steering (just as well given its vast by 19 inch diameter front wheels). It has air conditioning, electric windows and seats. It has a special spoiler at the back that acts as an air brake at high speed, but which can also be operated from the dash. So, when other drivers let you in, rather than giving a little wave of thanks, you can wiggle your air brake at them. That's what I call a boy's toy.

All this gadgetry, however, has added weight, hundreds of pounds of it, and the gossip is that McLaren were unhappy that Mercedes wanted to lard the SLR with all this kit.

The interior is certainly a lot fussier than it might be. Last week I had access to a Bugatti Veyron that was featuring at a launch for the new Bugatti watch by Parmigiani. It was rather simpler inside than the SLR, with fewer buttons and none the worse for that. All the same, the SLR is a fine place to be. Someone (like me) should point out to the makers of luxury saloons (Mercedes included) that you really don't need to fit your cars with vast World of Leather-style armchairs. The most ergonomically sound cars I've driven are also those with the thinnest seats and the least room for manoeuvre - the Vauxhall VX220 to name but one affordable example.

The McLaren Mercedes' seats are similarly well set up. You feel quite enclosed, once you've tugged those doors down into place (they are held aloft by huge gas struts) for the SLR is also quite a high-waisted design. Once you get used to it, the beast evolves into a semi-civilised immensely powerful grand tourer, the sort of cruiser you could imagine driving from your apartment in Paris to your studio in Milan, say, although given its 300 mile range you would have to stop to fill up rather a lot.

There is no easy way to convey the SLR's sheer presence. It looks much better "in the metal" than in illustrations. Before it was beamed down from its mothership, I had anticipated something that was basically just a rather muscley SLK. Wrong. It is over 15 feet long and six feet wide. The SLR is a big car with big wheels and big strakes along its flanks and makes a very big noise. With those wings - sorry doors - elevated and its amazingly sculpted bonnet open it has an exoskeletal quality. The only discordant feature is the nose; ugly and reminiscent of an old Proton or that face Basil Brush makes when he's disgusted.

But static or moving, no one ignores the SLR. As you pass what the Highway Code terms "other road users" their jaws drop and they you can lip read them mouthing "Wow!" like stunned goldfish. And that, too, is my last word on the McLaren Mercedes SLR after 124 exhilarating miles at its wheel. Wow.