An East Sussex observatory built in the Fifties has been given listed status.

Encased within giant domes, stargazers flock in their thousands to marvel at the sights provided by the Equatorial Group of Telescopes.

Their value has been recognised by the many schools and colleges who use the six telescopes as an educational tool.

The distinctive dome structures in which they are housed can be picked out from downland at Beachy Head, near Eastbourne, more than six miles away.

Now the domes and buildings at Herstmonceux, near Hailsham, have been lauded as a feat of architectural and historical importance.

The century-old concrete buildings were yesterday given a Grade-II* listing by the Department for Culture, Media and Sport as icons of architectural importance.

It means any alterations must respect their character and its preservation is taken into account when considering redevelopment plans.

They were built in the Fifties by architect Brian O'Rorke who made his reputation as a designer for the Orient Line's luxury liners.

Six other buildings gained listed status, including the 620ft BT tower in central London, the lighthouse at Dungeness, Kent, and the radar training station in Fleetwood, Lancs.

Stephen Pizzey, director of the Observatory Science Centre in Herstmonceux, said: "The listing effectively means changing the features of the buildings will be much more difficult to do.

"But we wouldn't wish to change anything. In fact, we've put a lot of time and effort into the restoration of the buildings."

Up to 45,000 visitors a year marvel at the sights provided by the telescopes.

Large-scale restoration work has been taking place using Heritage Lottery Fund cash and match funding from Science Projects Ltd.

Arts Minister Baroness Blackstone said the main purpose of listing them was to ensure care would be taken over decisions affecting their future.

Revealing the listings, Baroness Blackstone said: "Our building heritage should be about much more than old buildings. The best of our modern architecture also merits the recognition and protection that listing brings.

"These buildings mark the early milestones of Britain's transformation into one of the most technologically-advanced nations in the world today."

Sir Neil Cossons, chairman of English Heritage, said: "Britain was a world leader in telecommunications during the Fifties and Sixties.

"These new listings are a tribute to that scientific achievement as well as being architectural icons of the times.

"Listing will not impede the buildings' continued scientific work. Listing and scientific progress can work creatively hand in hand."

About half a million buildings in the country are listed, which means any changes to their structures have to be carefully considered.