Our sensational spy...

Our sensational spy shot shows, for the very first time, the key feature that should keep the second-generation model ahead of its rivals - an electric pop-up boot spoiler.

Similar to the system which is used by Porsche on its 911, the rear wing extends automatically as the car"s speed increases. As a result, lift is reduced over the rear end, and the tyres stay glued to the road.

The clever aerodynamic tweak replaces the fixed spoiler that appears on the bootlid of the current TT - an addition which was hastily introduced by the firm after early models were found to be unstable at high speed.

Not only does the ingenious aerodynamic solution make the TT safer, it also allows Audi to retain the trademark sloping rear window line and smooth curved bootlid of the original car when the spoiler is not in use. The rear wing will appear on all models in the range.

From launch, the TT will be available with two engines - a new 197bhp 2.0-litre FSI turbo and a 252bhp 3.2-litre V6. The former will enable the newcomer to cover the 0-60mph sprint in around 6.5 seconds and achieve a 140mph top speed, while the V6 model will have a 0-60mph time of less than six seconds and a 155mph maximum.

The first public unveiling of the all-new TT will be at September"s Paris Motor Show.

However, visitors to a special microsite (www.audi.com/tt) can view a teaser shot of the forthcoming model ahead of its launch.