A CLEANER diesel engine has been introduced by Audi aimed well and truly at company car and business drivers.

The 2.0-litre ultra engine has been designed not only to be highly economical but also to be low on emissions - critical when it comes to the tax drivers pay.

It makes the A4 saloon as frugal as a supermini with Audi claiming an official fuel return of 67.3mpg and CO2 emissions of 109g/km equating to £20 a year road tax and putting it in the 16 per cent benefit in kind bracket.

In the premium league dominated by German brands that's lower than a BMW 3 Series and on par with the new Mercedes C-Class.

The A4 ultra is priced £28,320, some £400 more than the 2.0 TDIe it replaces and while it matches the previous engine for power at 163bhp it is marginally quicker at 8.4 seconds 0 to 60 as well as being almost five per cent more economical.

That's no idle boast either and on the road we managed to record an average of 58.8mpg without any trouble giving the A4 ultra a theoretical range of around 800 miles on a tank of fuel.

The ultra has a six speed manual gearbox and although pull in the higher gears is noticeably lower than on other Audi diesels the mid-range performance is there if required.

It will hold its own with ease at motorway speeds with the long legged fifth and sixth gears used for cruising.

Gear shift indicators on the instrument panel are there to help get the optimum from the engine and the ultra is also fitted with a stop/start system to save fuel in traffic.

The version we tried was an A4 ultra in SE Technik specification and priced from £29,230 which includes leather upholstery and sat nav.

The ultra A4 sits on 17-inch alloys - not 18-inch as on other Technik models. That's a further fuel saving measure and so is lowered suspension to improve aerodynamics.

As with other A4 diesels - of which there are four - noise suppression inside is good with ride and handling to match.

The lean burn engine is backed up with a revised catalytic system which cleans up the exhaust output significantly, removing nitrogen oxides and hitting the new Euro 6 emission standards making the ultra the most fuel efficient A4 to date.

For its job on the executive scene the A4 ultra is absolutely fit for purpose and delivers a two per cent saving on the BiK front.

The ultra engine is also being fitted to the estate A4 Avant and to the A5 coupe as well as the larger A6 saloon where it costs from £30,985.