TWO members of a nuclear watchdog group are seeking assurances that opponents of nuclear power will not be put under illegal surveillance over their fight to prevent the construction of a Sizewell C plant.

Pete Wilkinson, a former director of Greenpeace who is now a Suffolk-based independent environment consultant, and Bill Howard, a member of Leiston-cum-Sizewell Town Council, believe they have been the subject of illegal scrutiny in the past.

Both are members of the Sizewell Stakeholder Group and raised the issue of surveillance following media reports that opponents of the Government's plans for new nuclear power stations in the UK were being monitored.

Their call for assurances – voiced at yesterday's SSG meeting at Aldeburgh – also follows a recent court case in France where nuclear industry officials have been prosecuted for a catalogue of illegal spying on opponents.

Mr Wilkinson said during the 1980s he had been on board Greenpeace ships harassed by government agents in France which is 80pc dependent on nuclear power.

'We had smoke grenades and tear gas hurled at us and police dogs were used to try to intimidate us. Once our ship was rammed as it tried to enter Cherbourg harbour,' he said.

Mr Wilkinson said surveillance by French government agents had got out of hand with the sinking of the Greenpeace ship Rainbow Warrior in New Zealand in 1985, an incident in which a crew member was killed.

Listening devices had been found when he worked in Greenpeace's London offices during the 1980s and the organisation had been infiltrated, Mr Wilkinson said.

He believes surveillance of protesters is routine in the UK, especially in politically sensitive areas such as nuclear power.

'Based on my experience I would not be surprised if attempts were made to monitor the activities of opponents of Sizewell C,' he said.

Mr Howard said that he was convinced that during the inquiry into plans by the Central Electricity Generating Board to build Sizewell B his telephone was tapped and his mail tampered with.

'I am looking for an assurance that this will not happen over Sizewell C,' he said.

A spokesman for EDF, the current owners of Sizewell B, said: 'For legal reasons EDF cannot comment on this issue at this stage.'