Porsche reveals hybrid Panamera GT

Porsche will build a hybrid version of its new Panamera GT car.

The four-door car will be powered by an electric motor, the car's petrol engine or a combination of the two, depending on conditions.

Average fuel economy with the hybrid system is expected to be around 15% better than with an equivalent petrol engine alone, with the car recording 31mpg.

The Panamera Grand Tourer goes on sale in 2009, but no date has been set for the hybrid-powered version to go on sale.

However, Porsche has already said that the Cayenne 4x4 will be its first car to use hybrid technology when it goes on sale in 2010.