Irish leaders were campaigning up to the last moment yesterday in a desperate effort to persuade waverers, with final polls showing the “yes” and “no” camps in the referendum running neck and neck.

“People realise it’s a big decision,” Brian Cowen, the Taoiseach and Fianna Fáil leader, said on the eve of the vote that is seen as pivotal to the EU’s future. “As we come closer to the day, I’ve always held the belief that the common sense of the Irish people will win out in the end.”

Today the Irish Republic will decide the fate of the Lisbon treaty. Every vote cast is absolutely vital to the outcome of a contest in which less than one per cent of the European Union’s population endorse or reject a blueprint salvaged from the wreck of the European Constitution.

Mr Cowen has been striving since the weekend to present a united front, with more than 90 per cent of the country’s elected politicians endorsing a “yes” vote on the ground of the benefits, past and future, that Ireland reaps from EU membership.

The message has been clouded by the confusion over what is in the treaty and what it will mean for Irish people. The “no” camp insists that it will sound the death knell for the Republic’s low-tax regime that has made it so attractive to US multinational companies.

“Europe has been good for Ireland, Ireland has been good for Europe, and . . . I can confirm without any equivocation there is nothing for us to fear in this treaty,” Mr Cowen said in Longford, in the Irish midlands.

Senior Fianna Fáil strategists are predicting a “yes” victory by a slim margin, but they admit that the turnout will be crucial. In 2001 the Nice treaty referendum was lost, an outcome attributed to a poor 34 per cent turnout, which was deemed to favour the “no” camp. The referendum was rerun a year later and the “yes” camp won in a 49 per cent turnout.

That means that the formidable Fianna Fáil electoral machine will be working flat out today, with party workers ferrying and chivvying voters to the polling stations.

A senior party figure said: “We are predicting a 52-48 per cent share of the votes in favour of a ‘yes’. An Irish Times poll of last week which put the ‘no’ camp five points ahead actually did us a favour. It galvanised our party machine and we detect that since the weekend the ‘no’ vote has peaked and we are resurgent.”

This would follow a pattern set in last year’s general election when Fianna Fáil started badly but gathered momentum to win its third consecutive victory under Bertie Ahern. Mr Ahern was forced to resign last month over lingering questions about his personal finances.

Ireland is the only EU state constitutionally obliged to hold a referendum. Finland, Estonia and Greece became the latest EU countries yesterday to approve the Lisbon treaty by parliamentary vote.

Mr Cowen has cleared his official diary tomorrow to deal with any potential fallout from the result. He was to have attended a peace conference in Donegal.

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