AUDI'S A8 stretched limo will become available with a plug-in hybrid power train early next year providing the company's flagship luxury model with an emissions-free, all-electric driving range of 28.6 miles.

The A8 L 60 TFSI e quattro, which measures 5.30metres with its extended wheelbase, will be available to order in the UK later this year, with standard wheelbase models joining the range a few weeks later.

First deliveries for both variants will commence soon after in early 2020 when the A8 plug-in hybrids will join the A7 Sportback 55 TFSI e quattro, Q5 50 TFSI e quattro and Q5 55 TFSI e quattro SUVs which have been available since September, signifying the start of the brand's commitment to its electrification strategy.

With a three-litre V6 petrol engine coupled to a powerful electric motor, the A8 pumps-out 443bhp of power and system torque of 516.3 lb-ft. with maximum torque available from 1,250rpm - just above idle speed. When both motors work together in boost mode, the A8 will accelerate from zero to 62mph in 4.9 seconds and reaches an electronically governed top speed of 155mph.

Although electric mode is likely to be used mainly around town, the hybrid A8 can drive on electric power up to a speed of 83mph and, according to Audi, it is capable of more than 90mpg under the NEDC testing regime. Fuel consumption figures under the more stringent new WLTP tests have yet to be revealed.

The A8 PHEV features what the German makers call an ‘EV soft key' which allows drivers to decide whether and how they want to adjust the interaction of the two motors at any time. The car starts in "EV" mode driving on purely electric power and the petrol engine is only engaged when the accelerator pedal is pressed beyond a specific resistance.