A former special advisor to the SNP warned Nicola Sturgeon that the prospect of a second referendum on independence before 2021 appears "very far".

Campbell Gunn, who served under Alex Salmond and Nicola Sturgeon, said that a future plebiscite would be held if the nationalists made it a key part of his manifesto before the next Holyrood election in just under three years.

Thousands of independence activists attend a rally at Calton Hill in Edinburgh in 2013. Photo: Getty

Thousands of independence activists attend a rally at Calton Hill in Edinburgh in 2013. Photo: Getty

The Prime Minister said that she wanted to see an IndyRef2 "during the life of this Parliament" if the UK, as expected, left the European Union.

Last month, Mike Russell, SNP spokesman for constitutional affairs, told PSM that a potentially uncoordinated Brexit would mean "an even greater urgency to give Scotland the choice of a different future".

Scottish ministers hope that the draft law establishing the framework for future referendums will be adopted by Holyrood by the end of the year.

Labor, Liberal Democrats and Conservatives oppose any IndyRef2, but the Scottish Greens vote means that the SNP has a potential majority for independence.

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But Gunn warned that the power to hold legally binding votes on the constitution being reserved for Westminster, the Scottish government still had to face significant obstacles to hold a meaningful referendum.

"I do not disagree with any of the Prime Minister's analyzes of how Scotland was treated during the Brexit negotiations," he wrote in Press & Journal.

"However, I must say that the likelihood of a vote in 2020 or even during the current session of the Scottish Parliament – just like what I would like to see is one or the other. the other – is really very far away.In fact, such electoral issues are not in the Scottish Parliament's gift – they are reserved for Westminster.

"We are currently in the midst of the election of the Conservative Party leadership, with the winner automatically becoming prime minister.The candidates have stated, one by one, categorically, some more energetically than others, that they are the only ones in the world. would oppose the approval of the Scottish Parliament in a referendum on independence, and that is it, frankly.

"Of course, the Scottish government could follow through on its plans, with the support of the Greens, the SNP could win a vote in Holyrood to hold a referendum, but it would have no legislative power and would only be considered". indicative ", without any weight in international law.And, of course, the opposition parties Unionist encourage their own supporters to boycott the vote, which would have the effect of avoiding any majority for independence."

Pamela Nash, Executive Director of Scotland in Union, said: "Campbell is right, which raises the question of why Nicola Sturgeon spends on him taxpayer-funded public resources and devotes valuable time to his parliamentary work.

"Only a fifth of the Scots want another referendum on independence in its calendar.

"She should give up her unwanted plan and resume the day-to-day work of repairing our schools, our hospitals and our economy.

"The majority of Scots are tired of playing and want to stay in the UK."