Volvo S60

Take Volvo. The Swedish firm has been offering dual fuel cars since 2000, but the latest are the most refined yet. And thanks to a loophole in London Mayor Ken Livingstone's proposals, you can avoid congestion charges by running alternative fuel. But how does the new Bi-Fuel S60 measure up? Two models are available ί¿½ one uses Natural Gas and the other, driven here, LPG.

On the road, the transition from petrol to gas takes only a touch of a button. The Bi-Fuel uses the standard car's 2.4-litre five-cylinder engine, and while it is less powerful, it's still swift and smooth. What's more, the ride is as silky and the interior finish as excellent as the standard S60's. But it's your wallet that will make you choose this Volvo. It's no more expensive than rivals, yet the fuel and tax savings are too good to ignore.