It’s a bold move, adding the word ultra to your product, and you can’t really blame people for being sceptical.

After all, it’s not as if the results are exactly tangible. Is that kitchen towel you’ve just bought really more absorbent now that it’s got ‘Ultra’ printed on the packaging, and just how much whiter can my whites actually get?

While I can’t say with absolute certainty that my clothes were any cleaner when I get out of the Audi A6 Ultra I do know that my credentials were a little greener.

Audi have waved a magic wand over their 2.0-litre oil burner and improved performance while reducing fuel consumption and emissions.

The improvements have been achieved without the aid of low rolling resistance tyres, compromised suspension settings or fiddling about with the aerodynamics, so you still get a proper A6 with its taught, angular lines and low-slung, purposeful stance behind Audi's trademark grille.

Step inside and Audi’s attention to detail is once again apparent. The instrument binnacle is easy to read while the two-piece centre console brings something a little different to what is a sumptuously appointed table.

Top quality switchgear complements the impressive MMI control system, which includes a clever touch sensitive panel next to the gear selector to aid sat nav inputs. Brushed aluminium inserts and leather seats - in S line trim - help to create an upmarket and exclusive environment.

The seats - manually adjustable with the exception of the lumbar support - are firm but comfortable and it's easy to find the perfect driving position.

I did find that the B-pillars compromised visibility a little at junctions, particularly when carrying a passenger, but that will vary depending on the driver's seat's position.

Leg and headroom is excellent front and back unless you’re planning on carrying a fifth passenger when the transmission tunnel’s size could be an issue.

There’s also room for 530-litres of your luggage with the seats in place, rising to 995 litres with them folded and there are plenty of cubby holes for all the bits and pieces that we will throw away… eventually.

There’s a little bit of idle diesel clatter audible from outside the car but the interior is very well insulated. The steering is a little vague but it does an excellent job of disguising the bulk of the car and the superb seven-speed gear box is the perfect partner for the punchy but frugal oil burner.

There are steering wheel mounted paddles for manually changing gear, but as I've mentioned before, with seven - and on occasion eight or even nine - gears to work your way through, any novelty would soon wear off. Their only real use would be for overtaking, but even then the dual-clutch transmission reacts quickly and seamlessly enough to make their use unnecessary.

And it is a punchy engine, despite the emphasis on economy and emissions. It's an improvement on the existing 2.0-litre diesel in every way that matters.

My other half, who is the most accurate measure of a car’s comfort, rates the Audi A6 a nine, it's not quite carpet of air territory, but it does a good job of smoothing out most of the bumps, lumps and potholes you'll encounter.

Compared to the existing 2.0-litre TDI, the Ultra is more powerful, offers more torque and lower emissions. That Audi have achieved all this without sacrificing any of the qualities that make the A6 such a great car is impressive. Ultra impressive.

Price: £29,645

As tested: £36,175

Engine: 2.0-litre four cylinder turbo diesel with stop/start

Transmission: Seven-speed dual clutch automatic

Acceleration: (0-62mph): 8.2sec

Top speed: 144mph

Urban: 55.4mpg

Extra-urban: 72.4mpg

Combined: 64.2mpg

Emissions CO2: 114g/km

Click here to find out more about Audi's range of cars.