Irish voters' approval of the European Union's Lisbon treaty has exposed divisions within Britain's opposition Conservative Party over how far to press their campaign against the treaty.
Following are views on how the Conservatives could deal with the Lisbon question, if they win a national election likely to be held next May, and the EU's probable response.
OFFICIAL CONSERVATIVE POSITION
Conservative leader David Cameron wants Britain, as a trading nation, to be in the European Union, but opposes the trend to "ever closer union" he believes is enshrined in the Lisbon treaty.
The treaty has already been ratified by the British parliament, but Cameron has promised a referendum on the treaty if the Conservatives win power and the treaty is not in force across the entire EU by then.
The treaty must be ratified by all members of the 27-bloc to come into effect and only Poland and the Czech Republic still have to do this. On Thursday an aide to Polish President Lech Kaczynski said his boss will sign the treaty into law on Sunday Oct. 11.
The Conservatives, well ahead of the ruling Labour Party in the opinion polls, say they would reverse British ratification if the country's voters rejected it in a referendum.
If the treaty is already in effect across Europe if and when the Conservatives come to power, Cameron says "we would not let matters rest there". He has refused to be more specific.
GRASSROOTS VIEWS
Cameron is under pressure from eurosceptic Conservatives to commit to holding a referendum under any circumstances.
The possibility that former Labour Prime Minister Tony Blair could become the EU's first president under the treaty has only sharpened grassroots determination to have a referendum.
If Cameron held a referendum when the treaty was already in force, and Britons voted "no", it would be difficult, if not impossible, for Britain to opt out of the treaty or persuade other EU states to make changes when there have already been years of tough negotiations.
Media reports suggest Cameron's threat "not to let matters rest" means that, even without a referendum, he will seek to repatriate social and employment powers to a national level and demand greater power over justice and home affairs.
OTHER VIEWS IN THE PARTY
The Conservative mayor of London, Boris Johnson, suggested this week that key parts of the Lisbon treaty, such as the idea of a European president or a European foreign policy, could be put to a vote in Britain even if the treaty were in force.
Daniel Hannan, a eurosceptic Conservative member of the European Parliament, said if the Conservatives took power with the Lisbon treaty already in force, then Britain should seek a "unilateral repatriation of power", going beyond the powers conferred by the Lisbon treaty to reclaim for Britain powers ceded to Brussels in previous treaties.
THE EU'S RESPONSE
To change the treaty once it is in force, Britain would have to launch a standard procedure which involves securing a simple majority of the EU's 27 countries to start negotiations on treaty changes and unanimity to approve them.
"It would be very difficult to find a majority to start a new round of negotiations. People are tired after almost a decade of negotiations on this treaty," one EU diplomat said.
OPTION OF LEAVING THE EU
Britain could leave the EU, using a provision of the Lisbon treaty which for the first time maps out exit paths. Charles Grant, director of the Centre for European Reform thinktank, said if Lisbon was in force and a Conservative government wanted to leave the treaty, but not the EU, the other 26 members would say: "The Lisbon treaty does have something that no previous treaty has had — it has an exit clause."
Britain has been a member of the EU since 1973. Analysts say that withdrawal would risk leaving Britain isolated diplomatically and could weaken trade ties with the bloc.
