SAD as it may seem, I can distinctly remember the first time I drove a diesel car. I had just joined Fleet News as a reporter and had until then spent my life being ferried about in, learning to drive in or blasting about in, petrol cars.

The editor of the time sent me to report on a driver training course and I slid behind the wheel of an old 2.0-litre diesel Rover 400.

When I turned the ignition key, the rough and ready engine grumbled into life. If my memory serves me right, I don't think it was even turbocharged, so as I accelerated on to the road from the car park, there was no surge of power, just a breathless wheeze to 3,000rpm before a change of gear was needed.

It was nasty, unpleasant, slow and a thoroughly disconcerting introduction to the world of economy motoring.

Fast forward just five years to the present day and things couldn't be more different. Take the long-term Mazda6 TS2 estate we are running.

It has barely covered 3,000 miles, but it is still a free-spinning unit which sends the rev counter swinging around its dial with little fuss.

After about 1,500rpm, there is a great surge of turbo-backed acceleration, which powers the needle round to nearly 5,000rpm without slowing.

There is little vibration and although the diesel engine is audible, I haven't found it a problem. Indeed, the low-down surge of torque encourages press-on driving, although that sort of motoring does nothing for fuel economy.

In the same way that it is now difficult to pick a bad car, so it is becoming increasingly difficult to pick a bad diesel engine.

Rocketing demand from buyers has made it worth the effort for manufacturers to invest millions of pounds in developing new units.

Diesel power is currently the 'torque of the town' among company car drivers and no wonder. It makes for a great driving experience, even before you take into account the tax benefits because of its low carbon dioxide emissions.

Our Mazda unit isn't Euro IV compliant, but it still beats its petrol equivalent hands down on emissions.

And seven months on from its Fleet News upper-medium car of the year award win, the Mazda still feels like a winning proposition. Build quality is excellent, with no rattles from the facia, although there has been a complaint that is a 'bit plasticky'. From the outside, I still think it is one of the best looking cars in its sector, particularly from the front, with its thin, moody headlamps and strong family bonnet lines.

And despite the heavy diesel unit sitting up front, it handles very well in everyday motoring, maintaining its composure when treated enthusiastically on bends. Having since swapped into a petrol car, which is admittedly more refined, I must say I am missing the low-down grunt of a diesel.

Clearly many other drivers feel that way, because diesel sales are heading for record levels this year.

Many drivers choosing heavy oil will never have experienced the days when diesels were dull and they are all the more lucky for it.

Company car tax bill 2003/04 (40% taxpayer): £135 per month