Bentley will display the world's fastest four-seat convertible at the Geneva motor show - capable of over 200mph.

The Continental Supersports Convertible will hit 62mph from rest in 4.2 seconds - only 0.1 seconds slower than the two-seat Audi R8 V10 Spyder - before smashing through 100mph in just over five seconds later. It will then keep going up to a follicle damaging 202mph.

Power is from the same twin-turbo W12 engine as found in the Supersports coupé, developing 623bhp. In a cursory glance to the environment, it will run on E85 bio-fuel as well as super unleaded.

Lightweight alloys, liberal use of carbon fibre in the cabin, ceramic brakes and thin sport seats mean that while the Supersports convertible is still a lardy thing - at around 2.4 tonnes - it's lighter than the four-seat GTC Speed.

But to be honest, we are not getting much by way of facts from Bentley at the moment, so you'll have to wait until Geneva for more. We could regurgitate the marketing: 'muscular styling,' 'supercar personality,' 'a pure Bentley driving experience,' and 'a distinctly sporting and contemporary style.' That wouldn't mean anything though.

Oh, but the E85 stuff is actually quite interesting. Owners can pump in any blend of petrol and E85 bio-fuel and the car will detect the ratio and adjust the engine management accordingly.

Discounting complex debates about the potentially detrimental wiping out of food growth to make way for more lucrative fuel crops, bio-fuel is by nature 'carbon neutral' - prompting Bentley to claim an overall CO₂ reduction of 'up to 70 percent' using E85 as compared to unleaded. Ah, how guilt-free the other half can live.

Pricing and on-sale date will be announced at Geneva, but expect little change from £175,000.

Mark Nichol - 17 Feb 2010