BMW 6-Series coupe

Although there are no official plans to add a diesel to the fleet, a BMW spokesman told us: "With the current popularity of performance diesels, never say never."

The most likely powerplant would be the 272bhp 3.0-litre twin-turbodiesel from the 535d. Its combination of performance and low emissions would certainly appeal to company drivers. The same unit is likely to be seen in the 7-Series and X5 in the near future, too.