THE diesel car market in the UK is predicted to double in size in the next four years - due mainly to 2002 company car tax changes - and two Japanese car giants are preparing to take full advantage. Toyota is currently introducing common rail diesels across its range and will bring in even cleaner diesels in 2003, while Honda will be introducing diesel for the first time in 2002 - both moves aimed at winning more company car business.

Nick Philips, head of corporate sales at Honda, says the company cannot afford to stay out of the diesel market, but will ensure the engine will not compromise the brand. He told Fleet NewsNet: 'It's a market-driven decision. Although we believe the petrol engine is more environmentally friendly than diesel, we cannot ignore the growth in the diesel market. Company car drivers are turning to diesel because the lower carbon dioxide emissions are a way of reducing their tax liability. But we are conscious that we cannot afford to compromise the quality and integrity of our product.'

The diesel engine is expected to be available in the Civic from early 2002, and will be built by Isuzu to Honda's own specifications. It will be a common rail unit and Philips said Honda would only introduce it when it is proven to be powerful and refined enough.

Toyota announced at Geneva that it would introduce a new diesel emissions purification system called DNPR (Diesel Particulate-NOx Reduction) for cars in 2003. The system, based on three-way catalyst technology, will reduce both particulates and nitrogen oxides in diesel exhaust gas. It is the first time a system which reduces both emissions has been devised and should make diesel engines even cleaner than before.