The Queen of England is having her two $14 million bespoke Bentley limousines converted to run on biofuels, the London Daily Mail reports.

This is part of a move by the British luxury car-maker to become more environmentally friendly - and a new biofuel-burning high-performance car is expected in the New Year.

The Volkswagen-owned, Crewe-based company is to produce a new range of engines which will offer a 40 per cent improvement in fuel economy by 2012, with all new vehicles able to run on the plant-derived fuel. But the ‘flex-fuel’ system, as it’s called, will also allow the vehicles to run on conventional petrol.

“We have a lot of support from the Royal Family for our biofuel strategy,” a Bentley exec tells the paper. “It is something about which they all take a keen interest.”