SOME people have diesels thrust upon them. Others are born to them. Among the former are 20:20 vision company car drivers looking forward to April 2002 when proposed changes to taxation could make carbon dioxide emissions a starting point for benefit-in-kind charges (most diesels emit substantially fewer grams of CO2 per kilometre than a similarly-sized petrol engine). The latter has been issued with oil-burners for years - never mind the noise, particulates, performance and higher front-end price, just look at those lovely economy figures and healthy residuals: wholelife efficiency is good for business.

However, diesels are on a downward slide in the UK. It remains to be seen, when the sales figures are published in next week's issue, just how they fared in June, but in April, for instance, diesel car fleet volumes fell 2.7% year-on-year, followed by a 15.4% plunge in May. Sure, the price of diesel has risen dramatically in the last couple of years, the market has been suffering new registration-plate jitters, and diesel's name has been blackened by studies claiming links between some diesel emissions and respiratory illnesses.

But such a sales decline is difficult to understand given the giant strides manufacturers have made in cleaning up diesel's act and image, and the British Government's apparent endorsement of diesel as a cleaner road fuel (although a 3% BIK penalty for diesel is now expected). And there are some fine diesels around: Volkswagen Group's three TDIs offer powerful arguments against petrol in VW Golf and Passat, Audi A3, A4 and A6, SEAT Ibiza, Cordoba and Toledo, and Skoda Octavia models. Fiat/Alfa's new 2.4 JTD not only performs well, it actually sounds good. And at the executive end there are excellent diesel options with Rover 75, BMW 5-series and Mercedes-Benz E-class.

State of the art honours, however, must go to PSA for the common rail engines in Peugeot and Citroen cars (vans and MPVs to follow). These high pressure direct injection turbodiesels (HDI in Peugeot 306 and 406, HDi in Citroen Xsara and Xantia), have done more for the diesel cause than anything that has gone before. In Peugeot's case the HDI was launched as a 110bhp unit in the upper medium 406 saloons and estates to replace the 2.1 turbo-diesel, transferring to the new-look 406 in April this year. There were no tongues in cheeks nor plugs in ears when HDI drivers and passengers said: 'I didn't realise it was a diesel.'

Apart from brief start-up (instant, no smoke) chatter, the 2.0-litre is as quiet, refined and quick as most petrol competitors - and it clears 50mpg in the combined cycle. Now there's a 90bhp version of the HDI to replace the 'old technology' 1.9-litre favoured by workhorse fleets.