The Government’s marine watchdog has granted a licence to enable safety work to begin on the off-shore rigs which once provided cooling water input and discharge services for the now-redundant Sizewell A nuclear power station.

The go-ahead, from the Marine Management Organisation, which regulates activities in the seas around England, is for the removal of parts of the structures which have deteriorated over the past few decades.

They include landing platforms and debris which may pose a danger to any members of the public ignoring warning notices not to board the rigs.

Major works will be delayed until later in the year because the structures house one of the UK’s biggest nesting colonies of kittiwakes.

With the birds already beginning to pair up, Magnox, which manages the Sizewell A site on behalf of the Nuclear Decommissioning Authority, has pledged to try to minimise disturbance.

But it is to press ahead with the removal of shipping navigation lights from the rigs. New navigation buoys will be installed in the sea nearby.

Meanwhile, a laser being used to deter gulls from nesting on the roofs of Sizewell A buildings appears to be succeeding.

Peter Montague, Sizewell A’s closure director, said the green laser swept over the roof tops and, while currently undergoing a period of testing, was proving to be an effective deterrent.

He said: “The gull situation was getting worse, year on year. “Last year roofs were damaged and gutters blocked. The birds are very aggressive and it got to the point where we had to do something.

“It does not harm the gulls, it just unsettles them and they fly off.”

Mr Montague said the use of the laser should eventually reduce nesting birds on site by up to 80%.

Work is also to be carried out at Sizewell A on a giant crane which suffered damage during Storm Doris last month. Two fixings became unattached leaving heavy cables dangling.

Sizewell A stopped producing electricity in 2006 after 40 years and defuelling is now complete, with work currently taking place to prepare for the care and maintenance phase to allow radiation levels within buildings such as the reactor safestores to naturally decay over time.