SEAT has vowed to continue developing and producing diesel engines for the UK market despite uncertainty over future demand for 'oil-burners'. Fleet diesel sales dropped for the sixth month in succession in June despite manufacturers ploughing billions of pounds into launching new diesel engine technology.

Elsewhere in Europe, diesel sales are booming but, in the UK, the Government has increased taxation on diesel at a higher rate than petrol. And the Inland Revenue is likely to announce that diesel cars will be hit with an additional 3% tariff on their CO2 rating when the new benefit-in-kind tax system is introduced in 2002.

But a spokesman for SEAT said that, with demand for diesels still high in Europe, it would not be deterred from including them in the range of vehicles planned for the UK. SEAT has revealed a new version of its Ibiza and Cordoba range which includes economical diesel engine options in the UK line-up.

Robert Couldwell, SEAT's business marketing consultant, said: 'Once a driver has got used to a diesel engine, petrol engines always feel lame because they don't have the mid-range punch that a diesel has. Diesels are getting better all the time and Volkswagen Group is developing its technology constantly.'