Scottish Liberal Democrat leader Willie Rennie has written to the First Minister asking him to clarify the SNP's position on the role of the monarchy in an independent Scotland. The letter comes after reports the Queen herself was concerned about her place in a dramatically altered Britain.
Mr Rennie told Alex Salmond to clear up his party's stance on the issue because of a 1997 SNP agreement stating a referendum would be held on the question of whether or not to keep the Queen as head of state for Scotland within the term of office of the first independent parliament.
In his letter, Mr Rennie said there were "many questions" on Scotland's constitutional future he hoped would be debated "in full" in the coming months and years.
However, he urged Mr Salmond to "clear up" the monarchy issue in the week the Queen marked 60 years since coming to the throne. The Queen is said to have a warm relationship with the Scottish First Minister.
Mr Rennie said: "The debate over Scotland's future has intensified in recent weeks after both the UK and Scottish Governments launched their consultations.
"Many questions on Scotland's constitutional future have been laid at the SNP's door, which we so far have received very little detail on.
"One of these questions relates to the future of the monarchy in Scotland."
Mr Rennie added: "Alex Salmond has said that the monarch would continue to reign in Scotland but this goes directly against his own party policy set in 1997.
"He said that he would respect the wishes of his party on this matter and no vote has been held by the SNP on this issue since then.
"The First Minister should now come clean and tell us what his party's policy is."
A spokeswoman for the SNP said: "Willie Rennie has blundered in trying to drag Her Majesty into political debate. Policies passed by the Liberal Democrat conference in 1997 certainly do not reflect the policies they are pursuing now, in cahoots with the Tories.
"Only last Sunday, former Tory Prime Minister John Major - Willie Rennie's Westminster coalition partner - welcomed the SNP's long-standing policy for the Queen to be head of state of an independent Scotland. With independence, we will retain the 1603
Union of the Crowns, and forge a new relationship of equality between Scotland and England.
"Since the establishment of the Scottish Parliament in 1999, the SNP's policy is for a referendum on a White Paper setting out the full details of independence - which will be published in November 2013, with the referendum taking place in autumn 2014 - and will include the SNP's long-standing policy for the Queen and her successors to be head of state."
The intervention by Willie Rennie comes a day ahead of talks between Alex Salmond and the Scottish Secretary of the Westminster government, Michael Moore. The two men will attempt to iron out their differences over the timing and nature of the Scottish independence referendum.