THE prospect of Independence Day on March 24, 2016 having to be postponed is raised today as the UK Government warns that, should Scots say Yes in September, the process of negotiation between the Scottish Government and the European Union would be lengthy, complex and uncertain.

The ninth Whitehall analysis paper from the Foreign Office and Treasury focusing on Scotland and international bodies casts more doubt on the SNP Government's ambitious 18-month timescale. On Wednesday, a raft of leading law experts branded it "risible" and "wishful thinking".

On matters of currency the report points out how the SNP Government's desire not to join the euro and remain in a common travel area with the UK and Ireland is "at odds with the EU's long established conditions of EU accession and is not in the Scottish Government's gift", noting how it would need all 28 EU Member States to grant unanimous approval.

"Scotland's negotiations to join the EU could be complex and long and the outcome could prove less advantageous than the status quo," the paper says.

The paper concludes: "Much may depend on whether an independent Scottish state would be willing to make concessions, which would allow the negotiations to be completed within their already announced timescale, or whether the date of independence would be postponed to allow time for further negotiation."

Before the paper's publication, Nicola Sturgeon wrote to Foreign Secretary William Hague. The Deputy First Minister wrote: "We have set out a clear and common sense approach to Europe in which Scotland will be an active and productive member of the European Union."

By contrast, she claimed the UK Government was flirting with an EU exit with its in/out referendum. Ms Sturgeon added: "It seems to me that your paper - to have a shred of credibility - must make explicitly clear that very real risk to Scotland of remaining in the Union."