THE SNP have been accused of plotting another independence referendum after a Nationalist MP tabled parliamentary questions on what “contingency plans” the UK Government had for one.

Margaret Ferrier, the Nationalist backbencher, has asked David Mundell, the Scottish Secretary, what the UK Government position would be if there were a majority vote for parties advocating a second poll in the 2016 Holyrood election and also what plans David Cameron and his colleagues had if holding a second poll were the policy of the next Scottish Government.

Ms Ferrier, who represents Rutherglen and Hamilton West, is expected to get a reply from Mr Mundell on Friday. Labour claimed she had “let the cat out of the bag” on her party’s true intentions.

Following the General Election, the Prime Minister was asked about the prospect of another independence referendum. He referred to how senior Nationalists had made clear during the campaign that the September 2014 poll was a once in a lifetime event, stressing: “There isn’t going to be another referendum.”

Despite the planned devolution of elections to Holyrood, Westminster remains the constitutional authority when it comes to holding referendums.

The PM’s remarks prompted Nicola Sturgeon to insist Mr Cameron had “no right” to rule out a second poll while her predecessor Alex Salmond suggested the SNP Government did not need Westminster’s permission and could hold its own indicative poll regardless.

The First Minister has suggested a second poll is “not on the immediate horizon” but expectations are growing that she will announce the inclusion of the option to hold one in the SNP’s 2016 Holyrood manifesto when the party meets for its annual conference in Aberdeen in October.

George Kerevan, the Nationalist MP for East Lothian, has already said he expects the party's autumn conference "to fizz with the question of putting a mandate for independence into the 2016 manifesto".

The tabling of Ms Ferrier’s questions was picked up by the Scottish Conservatives, which suggested they suggested the Nationalists were now “plotting a second referendum on independence”.

John Lamont, the Scottish party’s Chief Whip, said: “The SNP is going to have to accept that, less than a year ago the Scottish people spoke decisively on this matter.

“Of course, many ardent Yes supporters want another referendum; they’d hold one every day until they got the outcome they wanted.”

He added: “Instead of endlessly agitating for independence, SNP MPs should do the job their constituents sent them to Westminster to carry out.”

Ian Murray, the Shadow Scottish Secretary, commented: "While there is a crisis in our NHS and our police force, the SNP's priority is political tactics. They should be spending their time at Westminster focused on their constituents' interests, not on planning for a second referendum.”

The Edinburgh MP noted how it was less than a year since the 2014 referendum, which had provided a “decisive outcome” with more than two million people voting to remain part of the United Kingdom. “This,” he declared, “is the sovereign will of the Scottish people.”

Mr Murray added: “Nicola Sturgeon has said she has no plans for a second referendum. But few people will believe the SNP have given up on independence and it seems this MP has let the cat out the bag. We need to move forward and focus on creating a fairer Scotland with the powerful Scottish Parliament that the Scotland Bill will deliver."

In response, the SNP insisted the timing of any future referendum was entirely a matter for the people of Scotland, claiming “the people, not politicians, are in charge at every stage of the process”.

She added: "The First Minister has made clear we are not planning another referendum but, equally, has made it clear it is not in the gift of any politician and party to rule it out indefinitely."

Ms Ferrier was approached for a comment but did not respond.