The leader of the Scottish National Party has pledged to fight to keep Britain in the European Union as pressure mounts on the government to clarify its stance on the issue.
Prime Minister David Cameron has promised to hold a referendum on EU membership by the end of 2017, but both his pro-EU allies and eurosceptics within his ruling Conservative Party are growing impatient.
"David Cameron might play fast and loose with our place in Europe. Be in no doubt - the SNP will campaign positively for Scotland, and the UK, to stay in the European Union," Nicola Sturgeon told SNP party members on the last day of her party's conference on Saturday.
"We despair at the failure of leadership of a prime minister pandering to eurosceptics in his party, but unable to articulate clearly and precisely what it is he is seeking to renegotiate," she added, speaking in Aberdeen, northeast Scotland.
Cameron plans to renegotiate the terms of Britain's membership of the 28-member-bloc, but says he cannot guarantee he will get what he wants and has not ruled out campaigning for a British exit.
Critics say he has not been clear about his demands, which he says include more powers for London, limiting access to benefits for migrants and the ability to opt out of closer EU political integration.
Should a British exit from the EU appear likely, the SNP's opposition to the move could precipitate renewed calls for another vote on Scottish secession, following a referendum in September last year that saw 55 per cent of Scots vote to stay within the United Kingdom.
The SNP, the British parliament's third-largest bloc and an advocate of Scottish independence, sees the EU as an important trading partner and wants Scotland to have a "louder voice" in Europe.
"The time to propose another referendum will be when there is clear evidence that opinion has changed and independence has become the choice of a majority of people in our country," said Sturgeon, who is also Scotland's First Minister.
Speaking to some 3500 conference delegates amid regular bouts of huge applause, she also pledged to oppose government plans for British air strikes in Syria.
"What is needed is not more bombing but a renewed and intensive diplomatic initiative, led by the UN, to seek a lasting resolution of the conflict," she said.
Cameron is seeking cross-party support for British air strikes in Syria to fight the Islamic State group.