New research which suggests the amount of nuclear debris released during a fire at Windscale in 1957, was up to twice the volume previously thought, may be raised by Minister for Foreign Affairs Dermot Ahern when he meets British foreign secretary David Miliband today.
The fire - Britain's worst nuclear accident - resulted in a cloud of radioactivity across northern England, travelling as far south as London and on into northern Europe.
Mr Ahern, who is scheduled to meet Mr Miliband in London today, was last night said to consider the latest scientific research "extremely worrying".
The research carried out by John Garland, formerly of the UK Atomic Energy Authority, and Richard Wakeford, a visiting professor at the University of Manchester, suggests radioactive debris may have been as much as twice that initially thought. Moreover, it caused some 240 more cancers across Britain and northern Europe than had been originally estimated. The research was published in the current edition of Atmospheric Environment.
Dundalk, in Mr Ahern's Co Louth constituency, was the nearest Irish town to the the Windscale plant. Cancer rates and birth defects were some 12 per cent above the national average in the years immediately after the fire. However, a body of scientific opinion has always held that the radioactive discharge from the fire had been blown away from Ireland by the prevailing wind.
Nevertheless, a spokesman for Mr Ahern said last night that the Minister believed Windscale - subsequently renamed Sellafield - should be permanently closed.
"Mr Ahern is very deeply concerned that the incident of 50 years ago was a lot worse than we were led to believe. He will certainly be raising this with his Cabinet colleagues and at an inter-governmental level. It is not formally on the agenda for the meeting with the foreign secretary, but he will try to raise it with him if he can."
Meanwhile, in Co Louth a group which took legal action against British Nuclear Fuels and the Irish State for more than a decade, has continued to dispute what it calls "the majority scientific view" that the Windscale fire did not affect Ireland.
Ollan Herr, Constance Shortt, Mary Kavanagh and Mark Dearey spent 11 years attempting to sue British Nuclear Fuels - and the Irish State - maintaining that higher than average numbers of cancer clusters and birth defects in Co Louth were directly attributable to the fire in Windscale in 1957.
The group had its costs indemnified by the Dáil in the late 1990s, even though the Irish government was a defendant in the case.
Yesterday Mr Herr insisted that the group's scientific research has shown there was "something in the sea off the north Leinster coast which was corresponding to more cancers and higher birth problems than anything recorded in the west coast, the south coast or even the south Leinster coast".
The new research would, he said, add support to his group's arguments.
"It is a bit like greenhouse gases, it takes time for people to believe what is happening."
Prof Peter Mitchell, author of another study carried out by UCD, told the RTÉ television news that while the outer edge of the cloud may have just reached the east coast, a 2005 study found that that no radioactive materials made it to the northeast of Ireland.
The British authorities are at an early stage in planning for the extraction of 15 tonnes of damaged fuel rods, left in place after the 1957 fire which burned for two days.
The project is expected to cost €722 million (£500 million).