There's something rather imperious about a Mercedes S-class. Whether it's the 'best car in the world' or not, it's a vehicle that demands a certain respect. It's also a vehicle that demands at least 5076mm of parking space, something my driveway signally failed to yield. With its elegantly proportioned rump jutting into the pavement, I had to conclude that the S-class might have been a little too much car for me and my modest mortgage.

Everything about the S-class betrays a quite worrying attention to detail. The COMAND (Cockpit Management and Navigation Display) system is standard in all S-Class models and allows you to control all manner of functions. It's not as complicated as the iDrive system that BMW persists with in its 7 Series but it's still enough to reduce me to consulting the manual. This tome is thicker than my local Yellow Pages and I soon gave up. Mercedes claims the seats of this S-class have been redesigned to make them a little softer, spoiling a long-standing Mercedes tradition of rock-hard seating. It was always most entertaining to see somebody who'd never travelled in a Mercedes before to leap into the seat and then have that shocked expression akin to that worn by people who've just stepped off an unseen kerb. It seems Mercedes have now figured out how to make seats that are softer but still orthopaedically supportive. The optional Drive-Dynamic Multicontour seat is a wondrous thing, taking information from sensors that detect the car's steering angle, lateral acceleration and road speed and then adapting the seat in real time via a set of air bladders. There's ample room for five and the boot is large enough to qualify as an attractive bijou starter home if you were to park the S350 I tried in SW3. If you want even more room in the back, Mercedes will even sell you a long wheelbase version. After witnessing the inadequacies of my driveway, I'm glad I didn't opt for this when I selected my test car.

The latest generation S350 model is a far more satisfying proposition than its precedessor when you get comfortable behind the wheel. With 272bhp on tap, this car will sprint to 60mph in 7.6 seconds and continue right through to 153mph. Despite this huge increase in available performance, the S350 is actually less thirsty than its predecessor, returning a creditable average of around 25mpg. Mercedes have even managed to clean up its act on emissions a little, the S350 emitting 266grammes of carbon dioxide per kilometre. That still doesn't make it 'Herr Grun' in my book, but it's better than many of its rivals. The interior is a little brighter than S-class models of yore with revised switches, thin chrome strips, improved upholstery and an exclusive range of materials and trim options. Power is nothing without control and Mercedes have pioneered an innovative safety feature they dub Pre-Safe. This anticipates the threat of an accident and initiates preventative measures to deal with it. Mercedes' accident research has shown that there often tends to be a relatively lengthy time window between the moment an imminent collision is detected and the actual time it occurs. Pre-Safe uses sensors in the ESP stability control program and the Brake Assist system to judge whether a critical situation is impending. If so, the car will tension the seat belts so that optimum air bag deployment occurs, will move the individual seats into the optimum positions and will even close the sunroof if the vehicle begins to skid. Does it work? I wouldn't want to be there if it didn't.

Much as I'd love to, I get the impression that while the S-class may be from Mars, I am definitely from Venus. We're operating on separate social orbits and I feel rather self-conscious in a car that costs so much, especially when people gaze in to see who's behind the wheel. It's a towering achievement and, on merits, probably the finest car I've driven, but it's just a little too much for me. My other half on the other hand is asleep in it as I write. I've been forsaken.