A warning by the anti-Nice campaigner Mr Anthony Coughlan that "over-enthusiastic" count centre officials might be tempted to tamper with ballot papers to ensure a Yes vote in tomorrow's referendum were last night dismissed by the Minister for the Environment, Mr Cullen, as "an outrageous slur on the integrity of public servants".
In an e-mail sent to the Green Party and other anti-Nice activists, Mr Coughlan claimed that, in the event of a close-run vote, "there will be a big temptation for fraud by count centre officials who will all be appointed by the Yes-side political parties".
Mr Coughlan, who leads the National Platform organisation, added: "The main danger lies when bundles of Yes votes or No votes are added to the wrong piles. We are informed that this can happen massively in a tight referendum contest unless there are people there to watch out for it."
He later insisted the missive merely emphasised his belief that the referendum result should be seen to be beyond suspicion.
Calling on Mr Coughlan to issue a public retraction, Mr Cullen said: "No matter how strong the political arguments , the people of this country have always known that our electoral system is run to the highest standards of honesty and integrity."
He added: "It is increasingly clear that Mr Coughlan would say or do anything necessary to damage Ireland's position in Europe."
Speaking on RTÉ radio, Mr Coughlan accused Mr Cullen of blowing the matter out of proportion. The Minister had no right to "pontificate" over a private e-mail, he said.
Denying his missive suggested widespread corruption on the part of election officers, Mr Coughlan said there was a possibility that some individuals might be tempted to engage in fraud if the vote was poised on a knife-edge.
Mr Coughlan said his e-mail was merely intended to alert fellow No-campaigners of the important of being present when ballot boxes were opened.