Special Report on Diesel Cars: A touch of class for the market Cinderella: A once-poor relation is joining the luxury cars, writes Martin Derrick

THERE was a time when a new model would be launched in a fanfare of publicity, PR and an advertising blitz, following which the manufacturer would sit back and wait a year or more before introducing further variants such as GTi's or diesel-engined alternatives. That way the maker got a second bite of the cherry in terms of publicity while its engineering and design departments had time for a short breather following the work going into the all-new model.

But no more. Now competition in the marketplace combined with rapidly increasing demand means that while sports and performance variants can still afford to wait a while, diesels have to be brought to market with the minimum of delay. And so it is that just two months after the launch of the Citroen Xantia in Britain, two diesel derivatives have been introduced, just in time for the hoped-for August sales bonanza. Similarly, diesel-engined versions of the Peugeot 306 are now in the showrooms, little more than three months after the launch of the new hatchback range.

Peugeot is Britain's diesel market leader but with increasing competition - especially from Vauxhall - it needs the 306 diesel to enable it to maintain its position. Its upper medium saloon, the 405, is the best selling diesel car in the UK, not because the 405 is a considerably better car than the Ford Mondeo or Vauxhall Cavalier with which it chiefly competes; but because the PSA diesel engines, used by both Peugeot and sister company Citroen and also sold to Rover for use in the 200 and 400 Series ranges, are generally and deservedly reckoned to be the best small diesel engines in the world.

Citroen boasts that in launching a no fewer than six diesel Xantia models in time for August, it has won the race against the Ford Mondeo and Rover 600 to become the first of the new generation of upper medium cars to get a diesel to the market.

Not only are the Xantia diesels commendably quiet and refined on the road, but they also perform well. Turbodiesel models provide a maximum speed of 111mph and 0-60mph acceleration time in 11.6 seconds. Better still, official fuel consumption figures are 56.5, 37.2 and 41.4mph for 56mph, urban cycle and 75mpg respectively.

Vauxhaull is also riding the crest of a diesel wave at the moment. During 1993 alone it has launched four new diesel-engined cars, which have boosted the company's diesel sales by an impressive 150 per cent in the first five months of the year.

Until recently, very few diesel-engined executive and luxury cars were sold in Britain because they could not begin to compete with petrol-engined equivalents in terms of refinement and performance. Mercedes-Benz has offered diesel options for many years, as befits the company which was the first to put a diesel-engined car into volume production back in 1936.

Audi has also recently introduced diesel verions of the 80 and 100 series cars, which have demonstrated themselves to be sufficiently refined to win the What Car Best Diesel Car Award.

Yet BMW consistently refused to market diesel cars in Britain, even though they were available on the continent. All this changed in the last month or so, as BMW has now introduced a 325TD model, and will shortly offer both 3-Series and 5-Series turbo diesels.

'Times have changed and so has the perception of diesel', says managing director Tom Purves. 'There has also been a crucial change in image and in many ways the mere fact that BMW is now in the diesel marketplace will help change perception still further.'

In the off-road sector, where the Range Rover is still king, diesel technology is vital for success, partly because the low-revving, high-torque nature of diesels is perfectly suited to off-road driving and towing; but also because the economy of a diesel is a worthwhile selling point where a large petrol engine pulling a large and heavy vehicle on road can reduce fuel consumption to well under 20mpg in some cases.

Diesel has come a long way in a very short time.