Proton Impian 1.6 X Bi-fuel

It costs more than ΂£2,000 to fit, but with a 60 per cent rebate from the Government's Powershift scheme, buyers will receive a refund that brings the amount down to ΂£950.
The Impian has a potential range of over 900 miles, thanks to an 83-litre tank in the boot, although this reduces luggage space. But the loss of load capacity is compensated for by the fact that bi-fuel cars will be exempt from congestion charging, which starts in London next February before being introduced in other major British cities.

Around town, it's hard to tell the difference between running on LPG or petrol. However, on motorway journeys the Proton lacks power on gas and frequent downchanges are necessary to maintain momentum. Otherwise, the car is fairly good to drive, and the interior is packed with equipment, even if the overall finish is poor. But if you can live with that and want low running costs, the Impian is a sensible choice.