The British government discussed proposals today to give Scotland the legal powers to hold a referendum on independence, which could happen within the next 18 months.
Prime Minister David Cameron said a referendum should be held soon because the uncertainty about the issue was damaging Scotland's economy, although he remains strongly opposed to the break-up of the United Kingdom.
Scotland's deputy first minister Nicola Sturgeon, of the pro-independence Scottish National Party (SNP), accused Cameron of "a blatant attempt to interfere" in an issue that should be decided by Scotland and its people.
In elections in May, the SNP led by Alex Salmond won the first overall majority in the Edinburgh parliament since it opened in 1999, and promised to hold a referendum on independence.
Cameron's move is being seen as a ploy to force a referendum before the SNP wants it, in the belief that Salmond does not yet have enough support for independence.
The prime minister said ahead of a cabinet meeting at which the issue was discussed that the uncertainty about the independence issue could have economic consequences.
"This is very damaging for Scotland because all the time business is asking, is Scotland going to be part of the United Kingdom, are they going to stay together, should I invest?" he told Sky News.
"And we're beginning to see companies asking those questions."
Cameron's official spokesman said the discussion in cabinet was led by Finance Minister George Osborne, who is in charge of a committee looking into the Scottish referendum issue.
The spokesman said the government would set out its views to parliament "in coming days" after receiving final legal advice, but added that in the end it would be a matter for the Scottish people.
"Any decision on Scotland's future is for the people of Scotland to decide," the spokesman told reporters.
"The Prime Minister clearly has a view on the union and on the referendum, and he was setting that out yesterday, and he thinks that a referendum needs to be legal, fair and decisive."
It is believed Cameron's government will give its backing for a binding referendum, but with certain conditions.
These include that the referendum be held within 18 months, rather than the 2014 date planned by the SNP, and that it contain a simple question of whether Scotland should remain in the UK rather than multiple options, reports say.
The SNP has said it wants the vote in 2014 to coincide with the 700th anniversary of the Battle of Bannockburn, a famous Scottish victory over the English.
It is also thought to want a third "independence-lite" option instead of a simple yes-no referendum favoured by the British government.
Any decision is likely to heighten the already open hostility between Cameron and Salmond.
Speaking Sunday, Cameron claimed that Salmond knew "that the Scottish people at heart don't want a full separation from the United Kingdom".
"So he is trying to sort of create a situation where that bubbles up and happens, whereas I think we need some decisive action so we can clear up this issue."
His comments drew a furious response from the SNP.
Sturgeon said: "This is a blatant attempt to interfere in a decision that is rightly one for the Scottish government in terms of the timing of the referendum, and for the Scottish people in terms of the outcome of the referendum."
Salmond made it clear following his election success in May "that our position was to have a referendum in the second half of the parliamentary term", Sturgeon recalled.
Cameron said Sunday that he would be "desperately sad" if Scotland broke away from the United Kingdom, which he described as "one of the most successful partnerships in the history of the world".
The Scottish parliament currently has power on matters such as education, health, the environment and justice.
Key areas including foreign affairs and defence are still controlled by the British government in London.
Scotland and England came under the same monarch in 1603 and were offically united in 1707.