Hummer HX

Hummer is showing off a concept version of its smallest-ever vehicle at the Detroit motor show.

However, it's an open secret that the HX concept car is a dead-ringer for the H4 4x4 that will go on sale in 2009, and is tipped to be a rival for the Jeep Wrangler.

However, the production version is unlikely to feature the more outlandish aspects of the concept car, such as the removable roof panels and bumpers.

Power comes from an E85-compatible 3.6-litre V6 unit that is combined with a six-speed automatic gearbox and four-wheel drive.

One company official described the idea of a Hummer being powered by green biofuel as 'being akin to the world turning full circle' - but added that environmental pressure is now so great that, by 2010, every Hummer will be offered with a biofuel engine option.

He also conceded that further expansion of the Hummer brand is dependent on it developing smaller and more fuel-efficient cars.

The HX's short wheelbase is said to give it impressive off-road ability, with company officials saying it can tackle a 56-degree approach angle, a 51-degree departure angle and climb a 60% gradient.

Although there is no official confirmation, the H4's compact design and off-road capabilities are expected to mean it goes on sale in the UK.