 a sports car that runs on fuel made from cheese or wine, another that can run for more than 200 miles on a 10-minute charge of electricity, and a "Bio-Bug" powered by gas from sewage are among 20 vehicles of the future taking part in an eco-rally today.  Starting at Oxford this morning, the cars were due to make a two hour pit stop at the Building Research Establishment Innovation Park in Watford - allowing electric powered vehicles to recharge before continuing to The Mall in central London.  Now in its fifth year, the rally, sponsored by Bridgestone tyres and organised in association with the Prince of Wales's environmental initiative, Start, is designed to showcase low- and zero-emission vehicles.  Road transport accounts for almost a quarter of Britain's carbon dioxide emissions. While electric cars still cost more than their petrol rivals, a recent study by the Department of Energy and Climate Change claimed that the costs can be balanced out in the long run because electric cars are far cheaper to run. In a bid to promote electric cars earlier this year, the Government approved the construction of 11,000 charging points over the next 18 months, siting them in supermarkets, streets and car parks at a cost of ?400m.  Rising petrol prices and the recession are helping to steer people towards greener cars, according to andy Dingley, a spokesman for Bridgestone UK. "Vehicles that use fuels other than petrol or diesel are no longer concept cars of the future, but production cars of today," he said. This year has seen a number of car makers, including Mitsubishi, Nissan and Peugeot launch electric models. an electric version of the Ford Focus is due in 2013.  Last week, Ecotricity announced the first national charging network - with plans for charge points at 27 motorway service stations across the UK by 2014.  MOTORING PaGE 101