Minister for European Affairs Lucinda Creighton today said a Yes vote was in the State's interests after the Government set a May date for the referendum on the EU fiscal stability treaty.

This morning, Ms Creighton said amending the Constitution was a big choice for voters and that, while it was not for the Government to issue ultimatums, she felt “very clearly that it is in our interests to vote Yes”.

She told RTÉ's Morning Ireland that it was important to send out a strong signal of Irish commitment to Europe.

“We have to look at this from a national perspective as a starting point and say from the Irish recovery standpoint, what’s in our own best interests and the interests of small businesses around the country and potential investors in Ireland – the people who can create employment and contribute to our economic recovery.”

Ms Creighton said it people who believed Europe would continue to look after Ireland regardless of what way the vote went were living in “fantasyland”.

“I think Sinn Féin believes we can have all the benefits [of being in the EU] but none of the responsibility.”

The referendum date was announced in the Dáil yesterday by Tánaiste Eamon Gilmore following the weekly Cabinet meeting. He named Thursday, May 31st as the day on which voters will be asked to amend article 29.4 of the Constitution to ratify the stability treaty and adopt the legislation required to bring it into effect.

Mr Gilmore yesterday urged strong support for the treaty and insisted that it was entirely separate to the effort to secure an improvement in the terms of Ireland’s banking debt.

“I have always said that these two issues are distinct. The treaty is about stability for the euro. The talks on the promissory note are about getting a better way for the country,” he said.

Sinn Féin president Gerry Adams TD welcomed the announcement of the referendum date but said that his party would be campaigning vigorously between now and May 31st asking people to vote No.

“Sinn Féin believes this treaty is bad for Ireland and for the EU and will institutionalise austerity into domestic constitutional law and international law in perpetuity,” said Mr Adams said.

Elsewhere, a major international financial institute has said that a No vote will damage the country’s ability to borrow.

In Washington the Institute of International Finance, a powerful banking lobby which negotiated Greece’s €100 billion debt restructuring, said the referendum ranked among the current uncertainties that worried it the most.

“Putting it very simply, we worry about what happens if there’s a No vote. That throws the cat among the pigeons a little bit, specifically for Ireland,” institute chief economist Phil Suttle told The Irish Times.

“It would also raise questions about the strategy Europe is following in relation to the fiscal compact, possibly leading to demand for more referendums.”

The Government would have no right to draw aid from the European Stability Mechanism permanent bailout fund if voters reject the treaty, making markets more nervous about Ireland.

“Our general view on the Irish situation is: here’s your success story, and what we’re hopeful for is that that success story doesn’t get bumped off course.”

The institute, which draws its directors from Deutsche Bank, Commerzbank, Goldman Sachs, UBS, HSBC and Morgan Stanley, has told its members to be on alert for three strands of news from Ireland: economic performance following a new wave of fiscal austerity; opinion polls on the referendum; and “the rise of Sinn Féin” in polls.

“One of the things we notice is: Sinn Féin is quite supportive of taking a tough line on the promissory note issue. That’s something which will make international investors nervous,” Mr Suttle said.

Taoiseach Enda Kenny, who is on an official visit to China, stressed the importance of a Yes vote. “It is a statement of confidence about our country and about ourselves, it’s a statement for the future.”

Central Bank governor Patrick Honohan said yesterday that a deal to avoid the cash payment of €3.06 billion due this weekend on the bill for the Anglo Irish Bank and Irish Nationwide promissory notes was likely to be successful.

The plan to settle the payment with a long-term Government bond instead of cash in a deal expected within days would be a “very considerable step forward” and “a very definite gain” on the ability of the State to repay its debts, the governor told the Oireachtas Joint Committee on Finance, Public Expenditure and Reform.