A select few of Britain's motoring journalists have been fortunate enough to test drive the Bentley Mulsanne Speed – the sort of car they could presumably never own themselves.

But for potential buyers of the Mulsanne Speed, cost is unlikely to be a major consideration. The starting price of around £230,000 is only the beginning of the ultimate bill for the option-hungry Bentley lover. Want a fancy radiator mascot featuring the famous Flying B? That'll be another £2,200. Can't live without a refrigerated bottle cooler between the back seats? Cough up another £7,500.

There’s no doubt that the Speed is not an off-the-shelf sort of motor.

But let’s not get consumed by something as vulgar as cost. The Speed blends, well, speed, with luxury like few other top-end sedans. The hand-built 6.75 litre twin-turbo engine outputs 530bhp – up from the 505bhp of the basic Mulsanne (if 'basic' is a word that should be uttered in the same breath as 'Bentley') – while torque has been upped from a very-decent 752 lb/ft to 811lb/ft.

And this engine has some serious pedigree. Even today, some architectural similarities with the Bentley V8 of the 1950s are apparent. But modern additions such as twin turbochargers and a variable-valve-timing cam phaser have ensured that this old engine continues to compete with the best top-end sedan powertrains in the world.

In terms of fuel efficiency, the Speed was never going to win any accolades from green lobby. But the boffins at Bentley have actually improved the mileage of its mighty V8 by 13 per cent. That equates to another 50 miles from a full tank.

As regards acceleration, the 96-year-old manufacturer says the Speed can hit 62mph in just 4.9 seconds, eventually reaching a top speed of 190mph. Some believe these figures could even be underplaying the acceleration and quickness of the Speed.

Considering the barge-like proportions of this 2.7 tonne sedan, these numbers are mightily impressive. And although it can't offer the agility of large cars like the Audi A8 or Jaguar XJ, reviewers speak of a surprising nimbleness in the Speed.

Visually, this sportier update is not overtly different from the standard Mulsanne. Aside from 21 inch directional wheels, only the lightly tinted tail lamp lenses and the darker stainless steel trim remind us that this is a Speed.

Speed or Luxury?

For most billionaires in the market for a new runabout, they must choose between either speed or luxury (or buy a sports car and a high-end sedan). But the Mulsanne Speed offers both velocity and staggering opulence in spades. A cost saving of sorts, then.

Floor the pedal and the Speed rears back on its 21 inch wheels while its shiny nose lifts like a leopard sensing its prey. At the same time, the ever-present peril of spilling Tattinger on the upholstery is mitigated by the electronically massaged throttle tip-in, together with smooth transitions facilitated by the long-travel brake pedal.

That sense of control is perhaps behind reports that when the Speed really opens up, it doesn't feel as fast as it’s actually going. Three-digit speeds feel like cruising at well under 100.

Hire a chauffeur or drive-it-yourself?

While the standard Mulsanne targeted those tycoons with their own driver, the Speed wishes to seduce the type of buyer who might well drive themselves.

But any chauffeur that does get told to sit behind the wheel of this sumptuous speed-hungry beast is sure to congratulate themselves – once again – on their choice of profession.