Bentley Flying Spur Speed seen with plug-in hybrid system

Bentley is believed to be testing an upcoming flagship Speed variant of its new Flying Spur luxury saloon, and new spyshots show it sporting a plug-in hybrid powertrain. 

The Rolls-Royce Ghost rival was revealed a few months back in 'standard' form, but these prototypes are wear cues of a yet-to-be-revealed sporting model. These include a honeycomb grille and lower air intakes - classic Speed traits - what look like larger brakes shod in new wheels and rear-end disguise, possibly hiding a boot spoiler.

But the most informative object on view is a second filling flap on the left-hand side of the car. That's almost certainly a charging port used in a plug-in hybrid powertrain, set to debut on the normal Flying Spur soon and seemingly also destined for the Speed.

While nothing is confirmed, the Flying Spur shares its MSB platform with the Porsche Panamera, which is available with a 671bhp plug-in hybrid V8 powertrain in the Turbo S E-Hybrid. That seems the natural bedfellow for the Flying Spur Speed, offering as it does a 0-62mph time of 3.4 sec in the 2.3-tonne Panamera.