DAVID CAMERON'S Government yesterday told Scottish ministers they could end up in the UK Supreme Court if Holyrood held its own independence referendum.

In a day of explosive moves on both sides, the Tory-LibDem Coalition said its advice was the Scottish Parliament could not legally hold its own poll.

However, the Westminster Government's advice was that if it attempted to they could refer the process to the highly contentious court and effectively tie the SNP's hands.

Holyrood would be prevented from holding the referendum while the case was dragged through the courts for years.

Controversially it also emerged that either party in the Coalition Government would be able to force the Scottish Government to fight its case in court.

Both the Attorney General, Tory MP Dominic Grieve, and the Advocate General, LibDem peer Lord Wallace of Tankerness, individually have the power to ask Supreme Court judges to intervene.

First Minister Alex Salmond has previously demanded the Supreme Court stay out of Scottish affairs after it overturned Nat Fraser's conviction for murdering his wife in May last year and sent the legal system north of he Bor-der into a tailspin with a ruling on suspects' right to a lawyer.

A spokesman for Lord Wallace, a former Deputy First Minister, last night refused to rule out the possibility he could refer the referendum vote to the court, but said the Coalition hoped it would not come to that.

Officials were more blunt on the issue of a legal vote, describing a Scottish Parliament organised vote as not a referendum but "an opinion poll".

But as the row escalated on both sides of the Border, the UK Government also laid out a scheme to ignore Scottish ministers altogether and hold its own referendum, as part of a consultation launched yesterday.

As had been widely trailed, Coalition ministers set down a series of conditions under which they would "lend" Holyrood the power to legally hold its own vote. These include ruling out a second question on "devo max", or greater powers for Holyrood, the process is overseen by a watchdog such as the Electoral Commission, and that only over-18s can vote.

The Coalition also said it wanted the vote held "sooner rather than later", although an imposed deadline of 18 months that had been heavily briefed over the weekend was not included.

However, sources indicated the Coalition expected it would take until at least 2013 for the practicalities of a vote to be in place.

Scottish ministers reacted furiously to the list of conditions insisting no limitations should be placed on reflecting the will of the Scottish people.

Mr Salmond accused Mr Cameron of "Thatcherite" behaviour towards Scotland.

The Scottish Government hit back by claiming it did have the legal right to call the referendum although it indicated it could accept Westminster's offer, and ease fears over the legality of the vote, but only if it came with no strings attached.

As the row escalated, Coalition ministers poured scorn on the claim a Holyrood poll would be legal.

In a direct challenge to Scottish ministers, Scottish Secretary Michael Moore, who earlier in the day spoke to the First Minister in a conversation described as at times "grumpy", said he believed the SNP's plan would end up in court and they "would lose".

"Since when did we become a country where the law does not matter?" he added. "The Scottish Parliament does not have the power to hold a referendum."

Setting out the Government's preferred proposals to MPs, Mr Moore insisted he was making an offer in good faith to allow the vote, but certain safeguards had to be met. "This is the most important decision we as Scots will take in our lifetime," he said.

In its consultation paper, the UK Government effectively told Scottish ministers they could not hold an independence poll without their consent. It also set out three options under which it said it would allow the referendum to be run. The first two involve different legislative devices, the current Scotland Bill going through Westminster or a separate order called a section 30, which would effectively "lend" Holyrood the power to consult over constitutional affairs.

The Coalition says the law is clear that these matters are clearly reserved to Westminster under the Bill that set up the Scottish Parliament.

Both of these options would be subject to the conditions the Coalition has set out. The third and final option contained in the paper is the so-called nuclear option, the Tory-led Coalition at Westminster could call the election itself.

As the two governments battled it out, Margaret Curran, Labour's Shadow Scottish Secretary, said she hoped the argument did not descend into a fight between the two things Scotland rejects: "Separation and the Tories."

Ms Curran, who earlier called for cross-party talks, also criticised what she described as the "wrong signal" the two parties sent out by having Chancellor George Osborne, rather than the Secretary of State for Scotland, brief Cabinet on the plans.

Angus Robertson, the SNP parliamentary group leader, attacked the Coalition for trying to "dictate" the terms of the referendum. "The Conservative Party, the Liberal Democrats and the Labour Party opposed an independence referendum and each one of these parties lost heavily in the election. So, why is it this Westminster Government is trying to dictate terms about the referendum to the democratically elected Scottish Government, which has a mandate on this issue?" he said.

"Specifically, why is the Westminster Government seeking to dictate the date of the referendum, why is the Westminster Government seeking to dictate the questions on the ballot paper and why is the Westminster Government seeking to exclude 16 and 17-year-olds from this important and historic referendum?"