BRITAIN'S most economical car, the new SEAT Arosa SDi which has a claimed economy of 78.9mpg, will go on sale in April/May costing £8,295 on the road.

The compact supermini is the only diesel-powered contender in the emerging sector with the 1.7-litre 60bhp engine returning 64.2mpg on the Government's official combined cycle. The new car will debut at next week's Geneva Motor Show.