The issue of nuclear safety has been thrust into the limelight after the September 11 attacks in the U.S. and calls on Thursday by the head of the International Atomic Energy Agency for governments to improve security around installations.

Fenton said there was a lot of interest in nuclear safety especially after several media organistions overflew on Thursday British Energy power stations with small aircraft and helicopters.

"There are media stunts going on at the moment, but I am not sure what they prove. We could have told them there are not any no-fly zones," he said.

The Civil Aviation Authority (CAA) said some nuclear sites such as military installations and several power stations operated by state-run British Nuclear Fuels (BNFL) did have no-fly zones.

"The CAA can put in place no-fly zones, but the request has to come from the government," a spokeswoman at the authority said.

BNFL said it could not comment on security at its plants.

A spokesman from the Office for Civil Nuclear Security, the body that oversees issues relating to the security of civilian nuclear sites, said no-fly zones were a safety rather than security issue.

"No-fly zones are not there for security purposes, they are there for safety purposes," he said, adding that security at all nuclear installations was under review.

The Department of Transport, Local Government and the Regions, which handles aviation matters was not immediately available for comment.

Putting in place no-fly zones to cover Britain's 35 reactors is a long way off what other nations with nuclear power stations have done.

Last month France put in place ground-to-air missiles at its La Hague reprocessing site and said it will use warplanes to shoot down any hijacked aircraft threatening nuclear installations.