BENTLEY’S UPCOMING replacement for the Arnage has been spotted undergoing testing, giving us our first proper look at the proportions of the stately all-new sedan.

But with every panel bar the roof covered by a thick layer of plastic cladding, the sheetmetal of the new “Grand Bentley” is almost entirely obscured.

What we can discern however, is that this is a noticeably larger car than the Arnage. The photographer responsible for these images claiming it’s roughly 30cm longer than the Arnage.

We’re also afforded a peek at the new Bentley’s somewhat controversial headlamps, which are comprised of two circular lenses either side of the marque’s trademark mesh grille in an unusual - but certainly distinctive - layout.

Specific details about the car’s powertrain have yet to surface. It has been confirmed however that the venerable 6.75 litre V8 of the current Arnage will be put into retirement and an entirely new powerplant will find its way under the bonnet.

The British car maker says that the new engine will be flex-fuel capable and much more efficient than the old 6.75 litre. Current speculation says a cylinder de-activation system will also be employed.

Outputs in excess of 410kW and 1000Nm are also rumoured. It might be stately, but it won’t be a slouch.

GALLERY » 2010 Grand Bentley Spy Photos