A “plug-in” hybrid sports car that needs to be refuelled only once a year made its European debut at the Geneva Motor Show yesterday.

Fisker, the American company behind the new saloon, claims that if the car is driven for no more than 50 miles each day and recharged at night it could conceivably run on one tank of petrol for more than a year.

The rear-wheel-drive four-door car is powered by a small petrol engine and a lithium ion battery pack working in harmony. It also has an optional solar panel roof that helps to charge the car and keeps the interior cool.

Henrik Fisker of Fisker Automotive, said: “It’s a plug-in hybrid so you can plug it in at home like you plug in a mobile and charge it overnight.”

After 50 miles a petrol engine turns the generator that charges the lithium ion battery. Mr Fisker said the battery had a lifespan of more than ten years. He said the car’s secret was that it was always powered by the electric motor and not by the petrol engine.

The “Q Drive” hybrid technology that powers the Fisker Karma was developed by Quantum Technologies, which developed similar technology for the US military’s Delta Force, working on a vehicle that moves silently behind enemy lines and consumes a minimum of energy.

The Fisker Karma will have a starting price of £40,000 (dropping to £27,500 when it becomes available in Britain). Deliveries of the Karma will commence towards the end of 2009 with annual production projected to reach 15,000. The car is already sold out for 2009.