Bentley has revealed a new Continental GT, which goes all green by only having an eight-cylinder engine. Softies.

The new 4.0-litre engine has two turbos, so it's good for 500bhp, but it's 40 percent more economical than Bentley's mainstay 12-cylinder 'W12' engine that has exclusively powered the Conti GT since launch.

Expect Al Gore to order one any day now...

The new V8 will go in both the GT coupé and GTC convertible, and will be sold alongside 12-cylinder versions from the start of 2012.

A new eight speed automatic gearbox has been developed specifically for the twin turbocharged V8, driving all four wheels, and including a fuel-saving start-stop system too - Bentley's first.

The V8, developed with Audi, will therefore return around 25mpg combined fuel economy, compared to the 17.1 figure of the 12-cylinder, with CO2 emissions pegged at around 265g/km. Official figures are yet to be released.

However, those figures still mean the V8 Bentley is officially a gas-guzzler, according to the taxman, because it stays in the top VED band. However, in these times of economic austerity it's nice to know that reality TV contestants will have the chance to visit fuel stations less frequently.

The 567bhp 12-cylinder Continental GT hits 62mph from rest in 4.6 seconds, and while the V8 will be a little tardier, it's still expected to crack the benchmark in under five.

Little will differentiate eight-cylinder Bentleys from dozen-cylindered ones, but the V8 gets red Bentley badges, unique 'figure of eight' tailpipes, a black grille and the option of 21-inch black alloys.

It's expected to cost around £120,000, representing a £15,000 saving over a standard twelve-pot Conti GT. And with it's new found efficiency, the V8 Conti GT strikes us as the perfect learner driver's car. Or the perfect car to slap an 'L' plate on then run away, thus creating a news story.

Head to a dealer after New Year's Day to order one. A car dealer, that is.