Mercedes E300 BlueTEC HYBRID

This is the Mercedes E-Class E300 BlueTEC HYBRID – not only the most efficient E-Class ever but the most efficient large executive car in its class too.

Making its worldwide debut at the Detroit Motor Show next month and going on sale in the UK in the summer, it features a 201bhp 2.1-litre, four-cylinder diesel engine boosted by a 20kW electric motor.

Together with a lithium-ion battery pack, it can return 67.3mpg and emit just 109g/km – by comparison the current class leader, the non-hybrid BMW 520d Efficient Dynamics, does 62.8mpg and 119g/km.

However, while the 520d ED costs £30,435, the E300 BlueTEC HYBRID is likely to cost around £40,000. No acceleration figures are available yet but expect a 0-60mph time of around seven seconds.

The hybrid features stop-start and a ‘sailing mode’, whereby the engine is switched off when up to cruising speed on the motorway, allowing the electric motor to silently power the car. Available as a saloon and an estate, the installation hybrid pack is so compact that there’s no impact on boot space at all.