For years it has been the king of the American road - the bane of environmentalists and the joy of those wanting the biggest, baddest car on the highway. Yet now sales of the Hummer, made famous by Arnold Schwarzenegger, are skidding to a halt.

'The H2 has seen its day come and go. It does not seem to make sense any more,' said Wes Brown, a car industry analyst at Iceology, a market research firm.

The Hummer, a civilian version of the US army's Humvee vehicle, does 11 miles to the gallon, but is so large that it falls outside most fuel economy regulations.

'We need to buy cars more suitable for the environment. The Hummer is not one of those,' a Greenpeace spokesman said.

Part of the reason for the falling sales is a steep rise in the price of petrol. Buyers have turned to the Toyota Prius, a petrol-electric hybrid that does more than 50mpg.

But the Hummer isn't dead yet. Makers General Motors plan a smaller H3 model, which will use less fuel, and it is even developing a version with hybrid power.