Bentley first used the "Speed" name when it introduced a more sporty version of its 1928 Bentley 6½ Litre saloon.

The name reappeared in Bentley's 2001 Le Mans Speed 8 racing car, and then again in 2007, when the Volkswagen-owned company applied it to its Continental GT range.

The next obvious move was to use it for the Mulsanne, to signify a car that is sportier and more luxurious than the "normal" Mulsanne.

Apart from new exterior colours, the car has a two-toned interior done up by Mulliner, Bentley's customisation arm.

You will find diamond-quilted stitch lines on the leather upholstery, embroidered Bentley emblems on all the seats, and even the ceiling is covered in fine leather.

The wood veneer is made from actual blocks of wood honed down to a precise fit and mirror finish. And the metallic surfaces are made of metal, not plastic, such as a knurling of the gear lever and a coined finish to the door handle.

Opulence must be matched by might and the car's 6.75-litre twin-turbo V8 sees to that. The engine puts out 537bhp, up from 512bhp when the Mulsanne was introduced in 2010. It has 1,100Nm of torque from just 1,750rpm, up from 1,020Nm before.

As always, this massive power plant does best at low revs, working beautifully with an eight-speed ZF auto transmission. It allows the 2.7-tonne car to pull away from traffic effortlessly and reach 100kmh in just 4.9 seconds (5.3 for the Mulsanne). If given enough road, it reaches 305kmh (296kmh for the Mulsanne).

The Speed is so effortless and insulated that 150kmh on the highway feels like 100kmh.

Despite the increase in power, the Mulsanne Speed is more fuelefficient, thanks to the engine's cylinder deactivation system, which allows the V8 to operate as a V4 under light load situations.

The system works seamlessly and is undetectable.

Bentley claims the Mulsanne Speed is 13 per cent more efficient than the Mulsanne. That translates into another 80km a tankful.

It is still thirsty by any yardstick, gulping 14.6 litres of premium petrol every 100km and spewing 342g of CO2 every kilometre. Drive it like its name suggests and the car will easily treble that consumption figure.

The Mulsanne Speed is surprisingly agile for something its size. Its steering and chassis are pretty well-articulated, giving the driver a good sense of the road despite all that insulation.

Which is a good thing too, especially with its monumental prowess.

•The writer is a contributor to Torque, a motoring monthly published by SPH Magazines.