A network of radio telescopes across the country would listen for the alien equivalent of Hancock's Half Hour

British astronomers have drawn up plans to scour the heavens for signs of alien life using a network of telescopes that can detect broadcasts from other planets.

Seven major telescopes across the country would gather data for the project and send information over hundreds of kilometres of fibre-optic cables to analysts at Jodrell Bank Observatory in Cheshire.

The plans would establish Britain as the second largest centre for alien hunting in the world after the US, which has a number of projects dedicated to the search for extraterrestrial intelligence (Seti).

An advanced civilisation might make itself known by beaming messages into space, or by leaking local radiowave transmissions, just as early broadcasts of Hancock's Half Hour will by now have reached stars more than 50 light years from Earth.

Speaking at a Royal Astronomical Society meeting in St Andrews on Friday, Tim O'Brien, deputy director of Jodrell Bank, described how the array of telescopes, known as eMerlin, could join in the hunt for ET.

"We now have the capability to collect radiowaves across a wide swathe of the radiowave spectrum, and that allows us to look at the possibility of searching for the sorts of signals that might be created by ET civilisations," O'Brien said.

The work requires exquisitely sensitive radiowave receivers that can sift promising signals from the noise created by broadcasts on Earth and natural sources. Scientists expect alien broadcast signals to be sharper and to vary in different ways from those seen in nature.

The eMerlin telescopes are used around the clock to study exotic cosmic objects such as quasars, pulsars and dying stars. The cheapest way to hunt for advanced aliens is to pore over these data for evidence of their broadcasts.

But with more money, astronomers could do targeted searches and turn their telescopes towards regions of the sky where planets are known to orbit stars in the habitable zone, where conditions are neither too hot nor too cold for liquid water to form.

"Ask astronomers do they think ET exists and most will tell you yes," O'Brien told the Guardian. "We don't know what the nature of life would be, or whether it wants to communicate with us, but since we're collecting all this data anyway, it seems rather remiss not to search for ET signals."

If astronomers found signs of intelligent life, communication with the aliens would likely be fraught with difficulties. The language barrier would only be the start. "If it takes 1,000 years for our message to reach them, we are never going to have a scintillating conversation," O'Brien said.

Alan Penny, head of a newly established UK Seti research network, said advanced aliens may have remained elusive thus far for several reasons. They may have destroyed themselves before they had the technology to make contact with others. Or we may be alone. "The human race wants to know what's out there. And until we look, we won't know," he said.