Volkswagen-owned Bentley is unlikely to win any pro-environment awards for the fourth version of its Continental line even though CO2 emissions of both this and the 'standard' model are down 3.5% to 396g/km.

The new GT Speed is the most powerful production Bentley ever and the first to top 200mph (322km/h).

Its 600bhp (610PS) W12 engine develops 15% more torque and 9% more power than the standard Continental GT, while engine efficiency is improved on all models by the use of lower friction, lighter-weight components and a new engine management system.

The Speed, reviving a name from the 1920s, has a six-speed automatic transmission and four wheel drive, and a claimed top speed of 202mph (326km/h) and 0 to 60mph sprint time of just 4.3 seconds (100km/h in 4.5s).

Exterior changes, also shared with the standard Continental GT include a wider, lower air intake and more upright radiator grille that provides increased airflow.

Speed chassis changes include new, wider 9.5J 20-inch wheels and fade-resistant carbon ceramic brakes are optional. The new model has a dark-tinted front grille and larger exhaust tailpipes.

Power output of the standard engine remains at 552bhp (560PS) but the W12 now has internal efficiency improvements for a reduction in CO2 emissions of 3.5% to 396g/km, with a similar reduction in fuel consumption.

Engine changes include a new crankcase design to reduce internal losses, more efficient catalyst and exhaust system for improved emissions, lighter weight single chain drive for the camshaft and a new engine management system and faster response cam sensor.