THE prospect of driving a car capable of 205mph round an ice and snow-laden racing circuit can fill you with anticipation and dread in equal measure.

But far from pulling the plug on an exercise many would have cancelled, Bentley used the recent wintry onslaught to show off the four-wheel drive capabilities of the fastest production car the Crewe-based marque has ever built.

The new generation Continental GT Speed not only looks lean, mean and magical, its headline figures are simply mind-boggling.

Beneath the bonnet is what the Bentley boys call The Mighty W12, a 6.0-litre, 48-valve, twin turbocharged 12-cylinder engine, producing a thunderous 616bhp and 800Nm of torque.

The 0-60mph sprint is dispatched in a mere 4.0 seconds, top speed is 205mph - 8mph quicker than before - and power is transmitted via a close-ratio, ZF eight-speed automatic transmission, which makes a significant contribution to an overall 12 per cent improvement in fuel economy and CO emissions.

The engineering challenge of 205mph is an exacting one of course. That performance has to be both reliable and repeatable, so the engines are subjected to extreme bench tests.

They include four 100-hour full throttle tests - the equivalent of driving 20,000 miles - 400 deep thermal shock tests at minus 30 degrees C and to keep the engine cool more than 4,000 litres of air passes through the radiator per second.

Bentley as a brand is riding the crest of a wave at present, the past 12 months seeing a 22 per cent increase in global sales with 8,510 cars delivered.

That includes 1,104 cars in the UK which remains the company's third largest market after the USA and China.

And while the V8-powered Continental GT launched last year has proved a huge hit worldwide, the Speed is still responsible for around half the total sales.

But then if you can afford to spend a minimum of £124,000 on a Bentley, why not go the whole hog and shell out £151,000 for the most desirable version. What the hell, sensibly driven you can even squeeze 20 miles per gallon out of it.

So what do you get for the extra 15 grand it costs for the Speed over the regular 12-cylinder version?

As well as more punch and performance there are some styling tweaks, like a dark chrome finish to the mesh on the radiator grille and front air intakes, the ride height is fractionally lowered, damping  and steering systems re-tuned plus there are unique 21-inch alloy wheels and ‘rifled' tailpipes.

Move inside the handcrafted cabin and all Speed models are kitted out with the premium Mulliner driving specification featuring quilted, perforated leather and dark tint aluminium as well as carbon fibre finishes.

We took the Speed on an 80-mile mixed road and motorway route that led to the Thruxton motor racing circuit in Hampshire where much of the track was still covered in a mixture of snow, ice and slush - ideal for testing the Bentley's all-weather credentials.

Its all-wheel-drive system, biased 60:40 in favour of the rear, showed absolute stability even under hard braking and in the least friendly conditions.

Out on the road the Speed is a supreme traveller, beautifully refined, supple and civilised while capable of block-shifting during downchanges - jumping from eighth to third gear in an instant.

Flick the gear selector to Sport mode and baffles open for a deeper, more throaty exhaust note, so the car sounds the part too.

Even being as understated as the GT Speed undoubtedly is, it still looks and performs like a Grand Tourer on the one hand and a savagely powered sports car on the other.

A tab of £151,000 is a shedload of lolly, but among the realms of supercars there can be little doubt that Bentley is offering serious value for money with this car.