Jaguar engineers are currently hard at work on a diesel-powered XK.

Despite saying at launch that the coupe and cabriolet would only have petrol power, senior engineering sources have revealed that the economic situation has forced a rethink. So has the success of the BMW 635d.

Power for the diesel Jag will come from the uprated twin-turbo 3.0-litre version of the 2.7 V6 TD currently used in the company's saloons. It is likely to have over 250bhp on tap and should ensure that the XK is easily capable of over 30mpg in normal driving conditions.