RUNNING a junior executive car with a decent-sized engine has worked well for senior management over the past few years. Although their car comes with a petrol engine of about 3.0-litres, their high-mileage jobs mean they have not been taxed harshly.

However, from April next year they could be paying more than twice the amount in tax they currently pay under the new company car tax regime.

How do they continue to drive in the manner to which they have become accustomed without it hurting too much? The smart advice could be to downsize, but the really clever thing to do would be to opt for a diesel-engined car.

There should no longer be any prejudice over diesel cars, and Mercedes-Benz has recently introduced its 2.7-litre common rail diesel version of the C-class to the UK. The C270 CDI uses the same five-cylinder unit that powers the ML270 CDI sport utility vehicle.

With 170bhp it promises to be a lively performer with good economy. It needs to be good to compete with BMW's mighty 330d Sport, with 184bhp and the kind of torque you would associate with a heavy-duty off-roader. The ideal way to exploit this low-down grunt is through an automatic gearbox. However, currently there are few other rivals to match the Merc and the Beemer. Although the Audi A4 2.5 TDI quattro Sport matches its German rivals for power, there is no automatic gearbox option.

The next executive diesel to enter the fray will be from Volvo, whose new S60 D5 SE looks astonishingly good value. Developing 163bhp from a 2.4-litre five-cylinder common rail unit, it is the least powerful car here, but not by much. However, it is more than £5,000 cheaper than the Mercedes on-the-road, and like the Audi there is no word on an automatic yet.