The research programme, organised by the Search for Extra-Terrestrial Intelligence (SETI) Institute in the US, is called Project Phoenix. It is using the Jodrell Bank radio telescope in England and the huge Arecibo radio telescope in Puerto Rico.

Scientists believe they stand the best chance of finding out if there is intelligent life in space with radio observations.

This is because radio waves travel relatively unhindered through space and are easy to detect.

The radio telescopes have begun to look at several hundred Sun-like stars that lie within a distance of 200 light years.

Cosmic

Jill Tarter, Director of the SETI Institute, says: "By using the Arecibo and Jodrell Bank telescopes in the search we will have the most sensitive system possible."

The privately-funded SETI Institute has developed an ultra-sensitive receiving system that can sift through the cosmic static looking for any evidence of an artificial signal.

The receiver is located at the Arecibo telescope and will be used to make the initial detection of candidate signals. Jodrell Bank will then be immediately used to eliminate earth-based interference or confirm any suspected extra-terrestrial signal.

Previous searches for Life in the Universe have always been plagued by interference originating on Earth or from artificial satellites.

The search is being undertaken during two three-week observing sessions each year and will continue for several years.

Professor Andrew Lyne, Director of Jodrell Bank, said: "If an extra-terrestrial signal were detected, it would be one of the most dramatic discoveries ever made. We are glad that we can make a contribution to this exciting scientific quest."