A five-seater family car, with full luggage space, capable of more than 70 mpg (or less than 4 litres per 100 km) yet this car will go from 0-60 mph in 12 seconds and looks and drives quite normally. And there's more. Emissions are half the Euro 4 standard and will meet legislation up until at least 2010. Sounds too good to be true, doesn't it? Anthony Lewis reports.