From August, company car drivers will be able to drive away in the first Euro IV-compliant diesel convertible – the A4 Cabriolet 2.5 TDI.

For now at least, Audi seems to be the only premium car manufacturer interested in offering an oil-burning ragtop. Despite Mercedes-Benz's bravado in offering a diesel coupe in the CLK last year, and BMW's decision to offer a choice of diesels in the 3-series coupe, both of them seem to have got cold feet when confronted with the idea of combining wind-in-the-hair with clatter-in-the-ears.

The appeal for drivers lucky enough to have Audi's diesel convertible on their choice list is much lower tax liability. The first few months of the diesel A4 cabriolet came with the Euro III-compliant version of the engine, meaning drivers could not take full advantage of the lower carbon dioxide emissions of the TDI because of the 3% diesel supplement.

However, the 3% supplement is lifted on the latest front-wheel drive A4 models using the Euro IV-compliant 161bhp version of the 2.5 TDI engine.

The A4 Cabriolet is still the best-looking premium convertible on the market – more subtle than a 3-series and less fussy than a CLK.

With narrower headlamps than the A4 saloon and Avant, the Cabriolet looks a little sleeker, and its clean lines are emphasised with the roof down (electrically operated, naturally) thanks to the flat rear quarters.

The hood is accommodated in the boot, with a plastic cover inside to ensure luggage doesn't encroach into its space. The interior is typical Audi, although the dashboard has been prettied-up over the standard A4 and there is a little less room for rear passengers. You also have to warn them to duck when you begin to operate the roof four-up, as they might get a friendly nudge in the back of the head.

The A4 is an excellent car for posing in, and feels most comfortable when cruising. After-effects of chopping off the roof – squeaks and rattles from nooks and crannies – are minimal and the car is pleasant to drive, even with the six-speed manual version we tested.

There is also a Multitronic continuously variable transmission, even better suited to cruising, that does not hurt fuel economy or emissions.

OK, so it's a diesel and this is obvious when you turn the key. However, it also means you have the advantages of a diesel – excellent mid-range pulling power, up to 500 miles or so between refills and the lower benefit-in-kind tax.

On the move, even with the roof down, the car simply sounds as if it has a six-cylinder engine under the bonnet, and only the driver need know about it if he or she decides to select the optional engine badge deletion.

Model: Audi A4 Cabriolet 2.5 TDI
Price (OTR): £26,920
Engine (CC): 2,496 turbodiesel
Max power (bhp/rpm): 161/4,000
Max torque (lb-ft/rpm): 229/1,400
Fuel consumption (mpg): 39.2
CO2 emissions (g/km): 194
CAP RV (3yrs/60,000miles): £11,625/43%
On sale: Now