AT first glance there's not a lot to distinguish the Audi TT RS Roadster from the rest of the TT range, apart from the badges on the boot and grille.

But this one is special. The £48,000 price tag alone - almost twice the price of the entry level Roadster - tells you that.

And while it might seem hard to justify that sort of money for a TT it's all relative.

Paying that price buys you a car which is so quick it will go from standstill to 62 miles per hour in just 4.6 seconds - and that's faster than the V8 version of the TT's bigger brother, the Audi R8 Spyder, which will cost you twice the price of the TT RS. As I say, it's all relative.

The TT RS is certainly a car which has the raw power to outperform a number of the supercars of the motoring world while at the same time remaining relatively discreet, apart from a raised boot spoiler - a little odd as most TTs have a built-in one which only operates when the car is travelling at speed.

It's the first Audi model since the emblematic quattro coupes of the 1980s to feature charismatic five-cylinder power in a new high-tech form, boasting 340bhp. Recently the RS3 was launched with the same engine.

In both cases the engine is mated to a seven-speed DSG automatic gearbox with seamless changes and the combination makes this TT a real tour de force.

There is never any speed at which you can hit the accelerator on the TT RS and not get an instant response. It's the perfect car for when you need to move quickly, be it at busy junctions or islands or overtaking on the motorway.

Hit the Sport button near the gearshift and you not only get a sharper throttle response but a much deeper exhaust note as it opens a flap in the left exhaust tailpipe to further intensify the sound.

Move the gearshift from Drive to Sport and the RS redlines in each gear throwing you back in your seat. As you slow down from speed while in Sport the car blips the accelerator each time it changes down a gear as if you were driving on the track.

And if you do drive on the track the car has paddles behind the steering wheel for Formula 1-style gear changing.

The road-holding is superb from this all-wheel-drive quattro and it's a thrill a minute ride on twisting country roads. Somewhat surprisingly for a car with this sort of blistering performance you can still average around 30 miles per gallon.

Inside the car is finished exclusively in black, with brushed aluminium inlays and aluminium pedals.There's heated Silk Nappa leather sports seats - in a choice of colours - and a  thick-rimmed flat-bottomed steering wheel to make getting in and out easier.

Unusually the on-board computer also includes a lap timer for circuit use.