Size is also important. The A6 is considerably bigger than the outgoing model and isn't far off the A8.

Audi claims this is the biggest car in its class now, with the wheelbase stretched 8.3cm, overall length 12cm and width 4.5cm. Indeed, in terms of bootspace, which is a massive 546 litres – an increase of 112 litres over the old car – it is bigger than an A8.

When pictures of the A6 were first released, rather like Cyrano de Bergerac, most people couldn't get past staring at the nose. Audi calls it a 'trapezoidal-shaped' grille, and in pictures it looks overbearing. Not in the metal.

Get this car on to the street and it looks stunning, with a front end that is intense and mean. Business cars don't smile – they scowl. On the launch, seeing one in the mirror come roaring up behind really drove home what a magnificent piece of bold and imaginative design it is. The A6 will not suffer from the same problems BMW has had with the significantly less well resolved 5-series look.

The rest of the car's design is much more taut than the old A6, which had flowing curves, flat surfacing and a heavy-looking rear. Imagine an A8 that has been on the Atkins diet and endured some intensive gym sessions, and you're somewhere near. The interior continues the recent Audi tradition of building top quality interiors with a strong sense of

##A604--none##

Most Audis get a very symmetrical, rational dash layout but this has been changed with the A6. In order to give the impression this is a driver-focused car, all functions are grouped round the driver in a hooked panel shaped like a Saab's.

Interestingly, as BMW claims its iDrive system is to enable it to start removing switchgear clutter, Audi seems to have gone the other way. There are now more switches than ever, as well as its MMI system, first used on the A8 which is a technological marvel, and will keep kids and adults entertained for a long time with its brilliant graphics and endless options.

There is also a new steering wheel – all models are leather rimmed – with the new corporate nose shape included. Attention to detail also stands out. The aluminium strips around the wood on the door and dash are beautifully designed and finely made, and would befit a car of twice the price.

There are four engines at launch – the top-of-the-range 335bhp 4.2-litre V8, a 255bhp 3.2 V6 FSI, 177bhp 2.4-litre V6 and 225bhp 3.0 V6 TDI. In September, the range will get an entry-level 2.0 TDI, which Audi reckons will be the biggest seller by a distance, accounting for about 60% of total sales. Both diesels are Euro IV compliant.

There is no small petrol car on the horizon, according to Audi.

Prices rather neatly match the engine sizes. The 2.4 SE starts at £24,175, the 3.2 FSI SE at £30,225, the 4.2 quattro SE tiptronic is £42,775 and the 3.0 TDI quattro SE tiptronic £31,680. Audi believes those prices make it the best value for money in the segment, although with specifications yet to be inked in for the UK, that remains to be seen.

There are some ambitious targets for this car in the UK. In its best years, the old A6 found 7,000-8,000 homes. In a full year with the Avant (due in May 2005), Audi reckons to double that figure, which means conquest sales of some magnitude particularly, it believes, from BMW and Jaguar.

Such has been the success of the Avant in the old car, sales will be split 50-50 between the saloon and the estate. However, fleet sales could well see a marked drop, in percentage terms at least.

Business sales are down around 20% so far in 2004 across the segment, as more and more executives opt out of company car schemes and take cash instead. They are still buying the cars in this segment – the market is up 13%, but the cars are not being registered through companies.

Behind the wheel

Audi really wants this car to be the sportiest in its class. Achieving that goal starts off well on paper with the engines, which are among the most powerful in the segment when put up against the competition.

##A604 int--none##

The diesel in particular is a star, with 225bhp up against 218bhp in the BMW 530d and 204bhp in the E320 CDI. It also has 332lb-ft of torque and the latest generation 'piezo' common rail system.

Start it up and there is no hum or vibration, even when cold. Nothing is transmitted to the cabin at all. When moving, there's a distant, unobtrusive engine note, but even a diesel aficionado with the hearing of a bat would find it hard to distinguish it from the petrol versions.

Under acceleration, the car will just heave forwards quickly, and when allied to the six-speed tiptronic, the 3.0 TDI is a very easy car to make rapid progress in. The all-new 2.4 petrol V6 will be the smallest petrol engine and doesn't have four-wheel drive, but it is not overwhelmed by the size of the car, and does the 0-60mph sprint in a respectable 8.9 seconds.

Until the S6 and RS6 arrive in the next couple of years, the 4.2-litre is the largest and most powerful engine in the range, and while it isn't the most characterful V8 on the market, it does the job, is smooth and quiet.

Although Audi would like the car to be more of a sporty drive than the 5-series, first impressions suggest it isn't.

It's very difficult for a four-wheel drive car to feel as involving as a rear wheel-driven car because it has lots of grip, and doesn't move about as much. Consequently, the Quattro system gives the car superb traction with any amount of torque trying to rip the wheels free, and makes it feel safe, planted and secure. The electrohydraulic steering continues Audi's long tradition of inert feel with a little too much power assistance but it is precise and allows you to place this big car very accurately.

The ride quality seems to be similar to other Audis as well. That equals very firm, which means drivers of Mercedes-Benz E-classes will probably find it too unforgiving. Those who fancy a car that sits up nice and straight on corners will like the set-up, though.

Driving verdict

The new A6 is a glorious car. It looks wonderful, is built beautifully, has lots of great techy features and a strong line-up of engines. Choosing an executive express has got a lot harder – and even more fun.