Jaguar’s S-Type replacement, the XF, doesn’t go on sale until March but already the firm is working on a range-topping performance version.

This test mule is the XF R, powered by a supercharged version of the familiar 4.2-litre V8 engine and tuned to produce around 500bhp to tackle the might of BMW’s M5 and Mercedes-Benz’s E63 AMG.

There are several tell-tale clues to this car’s performance specification, including a black mesh grille, quad exhaust pipes and lowered ride height.

Expect to see a concept version next year, with sales likely to begin in early 2009.