It is worth saying from the outset that, not surprisingly, the brilliant new SL is not a fleet car. People at Mercedes-Benz don't even know how many will ever be bought with company money (although how many private individuals have £68,000 to spend on a car?). But please don't stop reading because there is a point to this.

The SL500 is a showcase, as is the Formula One team, for the peak of Mercedes-Benz technology, sophistication and style. The 'halo effect', as marketing bods like to call it, of cars like this helps to ensure the brand stays healthy and strong, from a £13,000 A-class upwards.

The aesthetic and technical values of the SL are visible enough in an A, C, or E-class, and can only help their popularity, and many of the stunning arsenal of tricks the SL carries will eventually filter down into the most workaday models that wear the three-pointed star.

And coming to a fleet car near you in the not too distant future will no doubt be a variation of the Sensotronic Brake Control fitted to the SL, which the firm claims is the first 'brake by wire' system fitted to a road car.

The pedal is connected electrically to the main brake cylinder and the brakes are hydraulically activated, via electronic signals. Apparently this gives better reaction times and shorter stopping distances: a potentially crucial 3% shorter at 70mph.

Pedal 'feel' is simulated by spring pressure and hydraulics. I found it slightly odd to start with, as the brakes did not feel very progressive - in fact slightly rubbery - although they do have awesome power. I did get used to it very soon though, and after a few miles didn't give it another thought.

The SL also has an adaptive accelerator pedal which sharpens its responses if it recognises that the car is being driven hard, but the real star of forward motion is the adaptive cruise control.

Ideal for when cheating Johnny Foreigner has kicked you in the ankle during the last minute of an important European game and you need to rest the swollen joint, the cruise control can be set to lock on to the car in front. It's not a new thing - the new Nissan Primera has a version - but the subtlety of the Mercedes system is amazing.

It has a programmable maximum following speed, and will hang behind cars up to the speed you set. Swapping lanes on a busy motorway, the beam latches on to whatever is in front immediately and almost imperceptibly adjusts its pace in unison. The motorway world will be a much safer place when more cars have adaptive cruise control of this sophistication.

And then there is the 'mechanical ballet' vario-roof. Lifting up a little flap just below the gearstick triggers 16 seconds of staggering engineering. Eleven hydraulic cylinders almost silently split the aluminium roof into three sections, which then fold elegantly into each other and slip into the boot.

Apart from transforming the SL into an even more stunning car, it also leaves a decent amount of room in the boot, of 288 litres, down from 206, which is certainly enough for a couple of big suitcases (Luis Vuitton, of course).

Although the roof encroaches on the aperture to reduce boot access, Mercedes has engineered another elegant solution. The push of a button on the sill of the boot lifts the folded roof sections up 20 degrees to allow better access.

To help shift its 1,700kg weight around, the SL has Active Body Control as standard, which uses hydraulically-controlled cylinders alongside the springs and dampers to contain roll, smooth out the ride and make it corner on rails.

It also has ABS with Brake Assist, Electronic Stability Program, bigger head thorax side airbags and a pop-up roll over bar to counter any peril of open-top motoring.

Prices start at £67,790 on-the-road, although very few will probably end up in the base spec. After all, what's a few extra thousand pounds on fancies when you have already spent such a huge amount?

In June the SL 55 AMG, with nearly 500bhp will arrive, costing £89,040, and will go head-to-head with the likes of Ferrari and Aston Martin for continent-crushing convertibles.

Mercedes-Benz has 1,250 SLs available this year and 1,425 in 2003, although should the managing director want one, get on the list sharpish. Waiting lists are two years already, although the firm believes this should dip at some point as speculators who have put multiple orders in at various dealers are weeded out.

Behind the wheel

There are very few wheels better to be behind than the SL500 when the sun is shining, the roof is down and you are dreaming of being a multi-millionaire or a Premiership footballer.

It is one of those cars, and there are a few out there but not many, that imposes its mood on you, rather than the other way round. It is a car that is staggeringly fast, and will hustle through bends if the paparazzi are on breathing in your exhaust fumes and you've got your popstar girlfriend's half-naked sister in the passenger seat, but on less tabloid-inspired occasions the SL will turn even the most hot- headed driver into a boulevard cruiser.

Thrashing this car is not the done thing, and will turn noses up around the marinas of the south of France, so be warned, because it encourages floating along in a state of luxurious grace. The 306bhp 5.0-litre V8 is just as serene as it should be, and even exposed to the air it is barely noticeable in the cabin until you really floor the accelerator, when there is a gentle growl rather than an undignified roar.

On the wind-in-the-hair front, those who need to keep their barnets well coiffured will find very little wind intrusion with the side windows and rear deflector up. The seats are probably the most comfortable in the world, adjusting in every conceivable way, and fan, massage, heat and cool the pampered occupant.

Mercedes-Benz is now grouping its buttons in stylish little herds rather than the rank and file lines of the S-class, and generally the interior is better than its saloon cousin and there is plenty of storage in the doors and behind the seats to ensure one doesn't air one's laundry in public, so to speak.

One gripe is that the plastic housing the cupholders under the TV screen felt cheap and wobbly, but that's pretty much it. It sounds picky, but why not - this car is tickling the toes of perfection so should demand the highest standards for everything.

The Tipfunction on the five-speed gearbox works well, allowing instant kickdown of a couple of gears, but would barely ever be used, because a huge wave of power is available the instant you prod your toe at any time, and the shifts between gears are barely noticeable.

The steering is weighted just right. It gives the driver a little bit of work to do, without actually being an effort and is sharp without being skittish.

If you really want, lots of lock and a bit of power will scrub the tyres hard sideways and get some squeal, but the ESP and ABC cut in discreetly before events start to get out of hand.

There is no doubt the fifth generation of the SL will continue its long tradition as one of the world's most desirable cars.