PORSCHE lifted the lid on a pair of new flagship 911 cabrio models - the Turbo and Turbo S.

The newcomers were launched to coincide with the 40th anniversary of the 911 Turbo.

The German brand says the cars will deliver the same blend of performance and efficiency offered by the Coupe model unveiled just a few months ago.

In the open-top 911 Turbo the 3.8-litre six-cylinder engine delivers 520bhp rising to 560bhp in the S model.

The cars can scorch from 0-62mph in 3.5 and 3.2 seconds, reaching a top speed of up to 197mph.

And all this while achieving fuel consumption figures not typically associated with such high performance - both returning 28.5mpg with CO2 emissions of 231g/km.

That's 30bhp more power and 0.2 seconds faster acceleration than their respective predecessors. They are also up to 15 per cent more efficient.

Boasting PDK dual-clutch transmission as standard and the new PTM all-wheel drive, as well as featuring rear-axle steering and active aerodynamics, the open-top 911 Turbo models are now also establishing leading Porsche technology in the open-top super sports car arena.

While the rear-axle steering has an immensely beneficial impact on handling for the two new models - both on the racetrack and during everyday use - the active aerodynamics can be tuned to offer optimum efficiency or driving dynamics at the touch of a button, depending on the driver's wishes.

Styling-wise the characteristic, widely flared rear wings of the new 911 Turbo generation are 28mm wider than those of the 911 Carrera 4 models - a virtually level surface of just over a hand's width extends to the outer edge of the vehicle.

Another eye-catching feature is the exclusive Porsche panel bow top with its lightweight magnesium frame, enabling the coupe-like arch to the roof to be achieved when the top is closed.

As with past models, the roof opens and closes in around 13 seconds, at speeds of up to 34mph.The cabin of the new Cabriolet models follows that of the 911 Turbo Coupe, the S version including an exclusive interior in Black/Carrera Red and adaptive Sport Seat Plus seats with 18-way adjustment and memory.

A Bose sound system is fitted as standard and, for the first time, a Burmester system is also available along with a radar-controlled adaptive Cruise Control system, camera-based road sign and speed limit recognition function and reversing camera.

Sales started with prices of £126,766 for the Turbo Cabriolet and £149,511 for the Turbo S Cabriolet.