SOME wag on the radio the other day said there were four distance settings you could dial into the cleverest cruise control systems to keep you safely behind the car in front.

They were: far/medium/close.... and Audi. Yes, when once BMW drivers were reckoned the pushiest on the road their place is now taken by people behind the four ringed badge.

Unfair, of course, to the many motorists who love their Audis and wouldn't dream of behaving like a bad tempered hooligan on four wheels. But you wonder if there might be something in it - especially in white.

Well, the Audi driven here is very much not the one for the more aggressive punter, who would miss the whole point of this cleanly styled businessman's express.

You can have your A4 with big and powerful petrol engines - or a mighty V6 diesel. There's all-wheel drive on offer too, along with huge alloys and masses of attitude. None of which do much for economy.

Or you can opt for an A4 with an 'ultra' tag, which brings with a 2.0-litre diesel in two power outputs (150 or 190 horsepower), along with unfashionably small alloy wheels - in Audi terms at least - and a general emphasis on saving fuel.

Like every new A4, the ultra version benefits from a substantial weight saving over the old model but added tweaks, including a gearbox that aims to keep the revs down, stop/start system and minutely lowered suspension for better aerodynamics all make the ultra.... well, ultra efficient.

Not nearly as efficient as the daft 72mpg Audi has to quote for its average economy, though. That's a figure arrived at the laboratory and doesn't reflect the real world, but it's what the rule makers say has to be done.

Out on proper roads and with only a little restraint you can persuade this big, comfortable and exquisitely built car to top 60mpg without much trouble.

Let this A4 off the lead a little and more than 500 miles of mixed use (including rushing to make a Heathrow flight without success) saw a final figure of 57mpg. That's properly ultra and a tribute to the thorough thinking that went into the car.

You can save £215 and choose the same A4 ultra with the less powerful engine and perhaps enjoy a tiny bit more economy (74.3mpg versus 72.4mpg officially) but I really wouldn't bother.

For the big surprise in this version of the A4 aimed at frugal motoring comes when you throw your fuel budget of the window and put you foot down. The car simply flies, picking up its elegant skirt and heading for the horizon.

Surprise number two; it makes so little noise in the process you wonder how a car could be much quieter. All those A4 drivers doing the firm's bidding on the motorways of Britain ought to arrive at their next appointment as fresh as a daisy.

Should they have to make many after hours forays they need to persuade the company car buyer to tick the matrix LED headlight option, a hefty £1,750 but providing the closest approximation of night into day I've ever driven behind. Quite spookily good, in fact.

Another £450 buys Audi's virtual cockpit, which turns the instrument panel into a TV screen, so you can have a huge sat nav map display directly below your eye line. How cool is that.