Some of the world's biggest motor manufacturers are in a race to develop an eco-car as good as a petrol- or diesel-run engine. Many of the contenders gathered in central London earlier as part of the Prince of Wales' Garden Party. The event is intended to highlight sustainable forms of travel. A host of famous names, including former racing driver Sir Stirling Moss and Dame Ellen MacArthur, drove a parade of green vehicles along The Mall to promote the eco-cars. On Friday, TV presenter Kevin McCloud and Mulberry creator Roger Saul, took part in a cross-country race driving electric-powered Californian Tesla supercars with a top speed of 125mph. They were also racing against the royal train carrying Prince Charles back to London from the Midlands after a four-day tour of the country promoting sustainable living. The pair had hoped to beat the train, but the prince arrived in the capital well ahead of the drivers. The journey by electric car cost £2 - £2.50 compared with around £13.67 for a vehicle that does 45 miles to the gallon. Source: Sky News