AS a youngster I remember being perplexed as to why Rolls-Royce and Bentley saloons were essentially the same cars with different badges.

I'm harking back to the era of the Rolls-Royce Silver Shadow and Bentley T-Type - the Bentley back then being simply a re-badged Roller.

These days the two famous marques have a lot more separating them, though they still represent the ultimate in sought-after and desirable luxury cars.

Somewhat bizarrely the other thing that unites them is that they're both German-owned, yet both seem as quintessentially British as fish and chips.

While Rolls sits at the pinnacle of over-the-top opulence Bentley's range offers a little more variety. As well as its two saloons it also has a grand tourer in the shape of the Continental GT, in effect the car that revitalised and reinvented the Bentley brand.

Several years on it hasn't changed all that much, though the current version is noticeably more curvaceous and muscular than its predecessor. The changes to the basic design blueprint are subtle but do make a difference.

Essentially there are three Continental GT coupes to choose from, an entry-level 4.0-litre V8, a 6.0-litre W12 and an even more souped-up version of that W12 in the shape of the GT Speed.

Given a choice between the V8 and the W12 I'd go for the V8. Even though on paper it's less powerful, the fact it's lighter makes it more fun to drive. But if that choice included the GT Speed it's fair to say the range-topper would win out.

The standard W12 is no slouch but the GT Speed takes it to a new level with genuinely thrilling supercar performance that's not for the faint-hearted.

A power hike to 616bhp means it boasts a top speed of more than 200mph and a 0-60mph time of just four seconds - around half a second quicker than the standard W12.

Enhancements include an adapted chassis, stiffer springs, new suspension bushes, anti-roll bars and adaptations for the electronic damping system and it sits around 10mm lower.

At 2,320kg it could certainly be described as a heavyweight, though the sheer power at one's disposal means this description is somewhat academic.

Putting it through its paces on an open road has an almost surreal feel to it in that it doesn't seem right that a car this big and heavy should go so quickly yet feel so light, nimble and agile.

It's alarmingly fast in a straight line and the fact it's four wheel drive, with a 40-60 front to rear split, gives a reassuring amount of grip when cornering. Going into bends at speed one can sometimes get a sense of just how heavy that front end is and also there were times I appreciated the added assistance of the carbon ceramic brakes (an optional extra that will set you back £10,405).

Talking of extras, there were quite a few on this car, the strangest of which was a boot carpet that costs £405. 

Despite its breathtaking pace, when the occasion demands it the GT Speed also performs perfectly well as an everyday car about town, though fuel economy for this type of toing and froing is a bit of a shocker.

It might have a combined economy figure of almost 20mpg but I rarely got close to this. For urban motoring overall economy ranged between 12 and 14mpg, though when driving enthusiastically on the open road I got between 15 and 16mpg.

As well as being a consummate and engaging performer the Bentley is also an exceptionally comfortable place to be. It rides beautifully and the interior combines the traditional with the modern to create an environment that is pure perfection. The use of wood in itself is a lesson in style and sophistication.