Jaguar will unveil its much-needed, 2.0-litre, diesel-engined X-type and an estate car counterpart for the company's highest-selling model at the Frankfurt motor show in September.

The £20,000 front-wheel-drive diesel, using a re-engineered version of Ford's four-cylinder, 130hp, TDCi power unit, is due on sale by the end of this year while the estate car will be in showrooms early next year.

Jaguar has accelerated development of its first ever diesel to compete for growing diesel demand among X-type class rivals, particularly Audi's A4, Mercedes' C-class and BMW's 3-series.

The X-type estate survived development budget cuts which eliminated a convertible and an R model.