While the Bentayga SUV is hogging the headlines, the company's engineers are currently busy testing a facelift for the Bentley Mulsanne, which, as these photos show, will be available in a new long wheelbase derivative.

The company hasn't applied too much camouflage to its LWB Mulsanne prototype, although there's a set a printouts obscuring the details of the car's revised headlamps, although the update looks as though it will retain the current car's quad-headlight arrangement.

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At the front, the air intake design now looks sportier than before, but the rear seems to be pretty much unchanged from today's car.

Along the flanks, Bentley has covered up the small vent built into the trailing edge of the Mulsanne's front fender. The company has also tried to disguise the diving character line just ahead of the rear door handle.

The big news, both literally and figuratively, though, is the length that Bentley has added to the Mulsanne's wheelbase. This has necessitated fitting new rear doors that dwarf their compatriots up front.

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Other than what we can see here, we have no other concrete info on the updated Mulsanne, although it's reasonable to expect a tweaked 6.75-litre twin-turbo V8, tech upgrades and a whole host of new rear passenger-centric features.