Scotland's First Minister Alex Salmond says his government plans to hold an independence referendum in 2014.
He said this date would allow the Scottish people to make a "considered" decision on Scotland's future within the United Kingdom.
The news came as the UK government said a referendum would be unconstitutional without its authority, the BBC reports.
It has said it wanted to work with the SNP-led administration amid a row over the timing and conditions for a poll.
Prime Minister David Cameron has warned that uncertainty over Scotland's future is damaging its economy and all three Unionist parties - the Conservatives, Labour and the Liberal Democrats - have called for any referendum vote to be held as soon as possible.
