There's no reason why this market shouldn't go from strength to strength

Neil Wallis, PowerShift

And car manufacturers are rushing to take advantage of the fast-growing market.

"Car manufacturers would be foolish to ignore the market's potential," PowerShift Manager Neil Wallis told BBC News Online.

Clean vehicles run on alternative fuels such as liquefied petroleum gas (LPG), compressed natural gas (CNG), or are hybrid or electric models which produce more environmentally friendly emissions.

Royal approval

The Queen is already a firm supporter of clean vehicles, with her fleet of Rolls Royces running on LPG, while many ambulances, police cars and buses have also switched away from petrol and diesel.

Many buses use alternative fuels

Other well known clean vehicles include the fleet of vans of both parcel carriers DHL and the AA rescue service.

The UK's number of clean vehicles was expected to rise to 15,000 last year.

But the market soared past expectations by 43% to reach 21,000. This is now expected to double again by the end of 2002.

"You can expect 2001 to be a watershed year for this market," said Director of Transport Action, Jonathan Murray.

Critical growth point

The demand for clean cars is now reaching a critical level for the manufacturers, allowing them to be integrated into standard production lines.

LPG vehicles have much less harmful emissions

This will then allow the companies to take advantage of the economies of scale and start to reap the benefits of the investment needed in clean vehicles.

Vauxhall and Volvo already have LPG cars as part of their standard production lines, and other car manufacturers are expected to follow shortly.

Oil companies such as BP and Shell have also launched wide-reaching expansions in order to offer alternative fuels at ordinary forecourts.

According to the report, one service station a day is adding an LPG pump alongside existing pumps, and one in 12 garages will offer the clean fuel by the end of next year.

Government help

The boom is almost exclusively due to the government's fiscal incentives aimed at kick-starting the market and cleaning up Britain's air.

You can expect 2001 to be a watershed year for this market

Jonathan Murray, Transport Action

A litre of LPG costs 40p at the pump, compared to an average price of between 72p and 80p for a litre of petrol and diesel.

In the March Budget, the government committed to maintaining this price differential for three years, offering further bonuses to fleets of company cars switching to LPG.

And Chancellor Gordon Brown set aside �30m for PowerShift to continue to supply grants for the conversion of cars to clean fuels and raise awareness.

"There's no reason why this market shouldn't go from strength to strength," Mr Wallis told BBC News Online.