Don’t judge this book by its cover! Under the familiar face, the revised A6 is a very different beast from its predecessor. It’s more refined, smoother to drive and its efficiency and emissions have been improved. And significantly, it has a more appealing price than any of its executive class rivals.

The world’s best-selling executive saloon is back! But while the updated Audi A6 doesn’t appear that different to its predecessor, make no mistake, its conservative looks hide big improvements...

There are now five petrol engines and four diesels in the line-up, and Audi expects the 2.0-litre TDIe we try here to be the best-selling unit.

There are two distinct versions of the 2.0 unit – the 134bhp TDIe (for economy) and the 168bhp TDI, and they are likely to account for 65 per cent of all sales within the A6 range.

The TDIe beats the BMW 5-Series and Mercedes E-Class in most respects. Off the line, it propels the A6 from 0-62mph in 10.3 seconds, yet returns 53.3mpg on the combined cycle and has emissions of 139g/km.

These figures are helped by a new six-speed gearbox, low-rolling resistance tyres, a more efficient power-steering pump and an alternator that charges the battery while the car is coasting.

The TDIe also has improved aerodynamics, thanks to a 20mm lower ride height than other A6 models, improved suspension and special spoilers which reduce drag.

It all adds up to a greener package that seems certain to ensure that the A6 is a big hit when it goes on sale in October – particularly when you consider the attractive £25,000 price tag.

Rival: Merc E220 CDI
Both cars offer supreme luxury, but the E-Class’s 2.2-litre engine isn’t as efficient. The premium price also plays its part.