A committee of British lawmakers at the House of Commons has concluded that the Scottish parliament lacks the power to hold a referendum on independence.
The Commons committee said that the Scottish parliament (Holyrood) does not have the power to hold a referendum on independence unless it is given it by Westminster.
The Scottish committee found Holyrood only has control over devolved matters, whereas the union between Scotland and Britain is a reserved matter.
"Any referendum must have an unchallengeable legal and moral basis, to avoid delays and challenges to the legitimacy of the process and its result," MPs found.
"The Scottish government has argued that Holyrood is legally competent to set up a referendum but the committee can find no evidence for this and the Scottish government has provided no legal justification for this view", the committee said.
The Scottish government intends to hold a referendum of the Scottish electorate on the issue of independence from the United Kingdom in the autumn of 2014.
The Referendum Bill is a proposed parliamentary bill to set out the arrangements for this referendum which is likely to be put forward in 2013.
A white paper for the Bill, setting out four possible options ranging from no change to full Independence, was published on 30 November 2009.
A draft bill for public consultation was published on 25 February 2010, setting out a two question yes/no referendum, proposing both further devolution, and full independence.
The Scottish National Party (SNP) minority government failed to obtain support for a referendum from other parties, and eventually withdrew their plan for a referendum before the 2011 election.
The SNP were re-elected in 2011 with an overall parliamentary majority, having pledged to hold an independence referendum if re-elected.
On 10 January 2012, the Scottish government announced that they intend to hold the referendum in the autumn of 2014.