Scotland’s First Minister Alex Salmond has insisted his government has a mandate to hold a referendum on independence in the autumn of 2014.
It comes after ministers in London said such a move would be unlawful without Westminster’s approval.
But a spokesman for Mr Salmond said Scottish National Party ministers were “entirely confident” of their plans.
The BBC’s Nick Robinson says it could mean an historic Supreme Court struggle between Westminster and Holyrood.
Mr Salmond said the timing would allow people to make a “considered” decision on the country’s future within the UK.
He said: “That’s the first date where you can have a full discussion and preparation for the biggest decision Scotland is going to make for 300 years.
“I think you’ll find the reaction of Scotland is that’s a perfectly satisfactory date for the referendum.
“It makes sure that everybody’s voice is heard in the consultation and all the questions that people have about the different constitutional formats can be answered and then we can have a proper campaign and debate.
“We’ve been thinking about these things for some time. I don’t think this will come as a great surprise to anyone and I think it will enjoy general support.”
In a row that could become a constitutional crisis, Mr Salmond accused the UK government of adopting a belligerent attitude.
Scottish Secretary Michael Moore said he hoped to work with the SNP government to resolve the dispute.
Mr Moore told the House of Commons that there would be a consultation on how to hold a referendum. He has not stated when the coalition government would prefer a referendum to be held, but said he would like it to be “sooner rather than later”.
In a statement to MPs, Mr Moore said the government’s “clear view” was that the power to hold a referendum was “reserved” to Westminster under devolution laws passed in 1998 and that the Scottish government could not authorise a referendum on its own.
Mr Salmond said Westminster should “resist the temptation” to interfere in Scottish politics.
“I think the Westminster parties have got to start understanding – all Westminster politicians – that this has to be a referendum made, built, and run in Scotland,” he said.
- BBC News