They claim the abundance of hydrogen in water could make it the green fuel of the future.

Experts at the University of Minnesota and the Weizmann Institute of Science in Israel have found that water reacting with the element boron produces hydrogen.

The gas is used to power an internal combustion engine or a fuel cell to generate electricity.

The researchers say a car carrying just 18kg of boron and 45 litres of water can produce as much energy as a 40-litre tank of conventional fuel. A prototype is planned by 2009.