Trade Minister Nigel Griffiths has told MPs he is satisfied with security at the Sizewell B nuclear power station.

His comments came in the wake of a protest on Monday in which Greenpeace activists broke into the plant on Monday.

There is no threat to the safe operation of the station which is still running British Energy spokesman

Mr Griffiths said the intruders did not reach sensitive parts of the plant, and public safety was not compromised.

The statement to the House of Commons came after the Tory MP Crispin Blunt asked if security was so lax that immediate action was required at other nuclear installations.

Earlier the environmental protesters were granted police bail after being questioned about a break-in at Sizewell B nuclear power station.

Vulnerability

Mr Griffiths said: "I am satisfied that the response procedures at the site were adequate and carried out according to plan."

He said there would be a full report into the incident by the DTI's office for civil nuclear security and British Energy and this report - which will not be published - would be used to review security arrangements.

Some of the 30 raiders from Greenpeace scaled the dome containing the pressurised water reactor at the Suffolk plant.

Campaigners say the break-in was to highlight poor security at the UK plant to highlight its vulnerability to terrorist attacks.

Commenting on the incident at his monthly press conference on Monday, Prime Minister Tony Blair said: "I am sure those in charge of security there will look at the situation carefully and review any lessons to be learned.

Protestor on the pressurised water reactor

"But ... of course there is an ongoing continuing threat and that's the very reason why this is so important to deal with."

However a spokesman for British Energy, which operates the plant, criticised the stunt.

He said: "There is no threat to the safe operation of the station which is still running.

"This is a highly irresponsible act by Greenpeace who are endangering themselves and others by risking injury from falling from the roof."

Volunteer Rob Gueterbock, who was one of the protesters on the reactor dome, said: "Sizewell B is easier to get into than a Norwich nightclub.

"It is a terrifying thought that if we can do this then anyone can."

Mike Harrison, the maintenance manager at Sizewell B, said security had been improved following a previous protest by the environmental group.

He said the protesters had damaged insulation, broken through a fence, and smashed a door to get in.

In October more than 40 protesters occupied the site before peacefully ending their protest.

British Energy operates eight of the most modern nuclear reactor power stations in the UK, including Sizewell B.