LONDON British opposition leader David Cameron renewed his pledge on Saturday to hold a referendum on the EU's reform treaty if he wins power next year and the treaty has still not come into force.
Irish voters backed the treaty in Friday's referendum, leaving the Czech and Polish leaders as the only heads of state that have yet to ink the document before it can take effect.
"I want to make one thing clear: there will be no change in our policy on Europe. There will be no change in Conservative policy as long as the Lisbon Treaty is still not in force," said Cameron, who leads the center-right Conservative party, widely tipped to win a parliamentary election.
"I have said repeatedly that I want us to have a referendum. If the treaty is not ratified in all member states and not in force when the election is held, and if we are elected, then we will hold a referendum on it."
The British parliament ratified the Lisbon treaty after the Labour government rejected Conservative calls for a referendum.
The Conservatives say they will reverse Britain's ratification if voters reject it in their planned poll.
Ireland's Prime Minister Brian Cowen on Saturday declared victory for the Irish government's "Yes" campaign just before the end of vote counting. "It is a good day for Ireland and it is a good day for Europe," Cowen said.
Despite the convincing yes vote, Euroskeptic Cameron said he would name the referendum date during the election campaign.
"The Czech prime minister has said that the constitutional challenge before the Czech Constitutional Court could take three to six months to resolve," Cameron said.
Cameron also said that even if the treaty, designed to speed up decision-making, were ratified by all members the Conservatives would continue to fight it without spelling out how he would do that.
The Tory leader is mindful some Conservative right wingers want a referendum even if all EU states have ratified it.
A survey of 2,205 party members undertaken by the ConservativeHome.com website for the Independent newspaper on Saturday found that more than eight in 10 supporters want him to call a referendum even if it is approved.
"We have repeatedly said we would not let matters rest there. But we have one policy at a time, and we will set out how we would proceed in those circumstances if, and only if, they happen."
(Reporting by Stefano Ambrogi; Editing by Alison Williams)