A discovery by British scientists could potentially mean the end of the petrol engine.

Researchers from Newcastle and Liverpool universities have found a new safe way of storing and releasing hydrogen to produce energy.

The breakthrough, which involves injecting the gas at high pressure into tiny pores, could pave the way to environmentally friendly hydrogen-powered vehicles.

Hydrogen is a much cleaner fuel than petrol or diesel since the only waste product made when it burns is water.

A hydrogen-powered car would not contribute to global warming by generating the greenhouse gas carbon dioxide, or churn out noxious pollutants.

But at present hydrogen is simply not a practical fuel alternative. Storing enough of the gas to provide sufficient range and power has proved an impossible challenge.

Now scientists at the universities believe they have taken a first step towards solving the problem.

The key is to use porous materials containing holes a hundred thousand times smaller than the thickness of a sheet of paper.

Professor Mark Thomas, of Newcastle University's Northern Carbon Research Laboratories, said: "If developed further, this method would have the potential to be applied to powering cars or any generator supplying power.

"Although hydrogen-powered cars are likely to be decades away, our discovery brings this concept a step towards becoming reality."