In an interview with Germany’s Auto Motor und Sport this week, Winterkorn answered questions about the state of Volkswagen’s upper luxury marques, saying: “With Bentley we will react to the changing market conditions. I could well imagine a six-cylinder twin-turbocharged diesel in a Bentley.”

Winterkorn’s comments oppose those of Bentley boss, Franz-Josef Paefgen, who recently told journalists that Bentley was not planning to introduce a diesel engine in any model.

The diesel referred to by Winterkorn is a new twin-turbo 3.0-litre V6 common-rail unit presently undergoing development by Audi. Rumoured to deliver over 300bhp and over 440lb ft of torque, it should be unveiled in the third-generation A8 at next year’s Frankfurt motor show.