Vauxhall Corsa 1.2 Dualfuel

The C-charge-exempt Corsa Dualfuel has been on the firm's price list since May, but the first cars are now being delivered - so we took one for a spin. In standard form, the efficient Twinport petrol engine is capable of returning 48.7mpg, but when running in LPG mode - engaged by flicking a switch on the dash - that falls to 38.2mpg.

However, with the lower purchase price of LPG, this Corsa still offers big savings, and you'll be hard pressed to spot any differences from behind the wheel. Drivers will notice a slight hiccup as the car switches to LPG, plus a minor drop-off in performance - it adds 0.3 seconds to the 11.8-second 0-60mph time in petrol mode. The car also revs more smoothly on conventional fuel, although the difference isn't obvious.

Otherwise, it's standard Corsa, and as a result is now feeling dated - an all-new model is due next year. The Dual-fuel also has one significant downside. The 38-litre LPG tank is fitted under the rear of the car. While it doesn't harm luggage capacity in this position, it takes up the spare wheel's space - so there's a can of get-you-home foam instead of an extra tyre.

Still, buyers will be able to content themselves with the Corsa's impressive CO2 emissions rating of only 119g/km. That figure rivals city cars such as the Smart ForTwo, without demanding any compromises in practicality.