LEADING SNP Brexiteers have warned the party against backing a second referendum on leaving the European Union.

MSP Alex Neil said the move could “set a precedent” for overturning a vote for independence, while former party depute leader Jim Sillars predicted the policy stance could result in the SNP losing the next Holyrood election.

First Minister Nicola Sturgeon is under pressure from her own colleagues to announce plans for a second independence vote, which is partly in response to Brexit.

However, Noel Dolan, Sturgeon’s former Government adviser, said the SNP should back a referendum on the final Brexit deal.

His call is privately endorsed by senior party figures, but the move risks alienating the pro-Brexit supporters in the SNP. It has been claimed that around one third of SNP supporters may have voted to leave the EU.

Paul Hutcheon Analysis: Why backing a Brexit referendum could help the SNP

Neil, a former Health Secretary, said a combination of factors influenced his vote, such as the increased support for right-wing parties in Europe, austerity measures imposed on Greece, and former chancellor George Osborne’s threat of an emergency Brexit budget.

Asked about Dolan’s view, Neil said: “It would be a mistake for the SNP to support a second Brexit referendum as it would set a precedent for undoing a future vote in favour of Independence. It would be a hostage to fortune which would undermine independence.”

Sillars, the former Glasgow Govan MP, also voted for Brexit. He said trying to get back into the EU would be inconsistent with the SNP's opposition to Westminster taking charge of policy areas devolved to Holyrood, when they are repatriated from Brussels.

He said: "They've made a song and dance about Westminster keeping the powers and I agree with many of the points they [the SNP leadership] have made. But that stance is contradictory with wanting to transfer those powers back to Brussels."

Sillars said there was widespread confusion among voters about the SNP's position on the EU. He said: "A number of people outside of politics have said that they think this is contradictory. It's not just people in politics saying it. I would not vote to rejoin the EU, which is on its way to becoming a united states of Europe. I also think that many people who voted yes in 2014, but who voted leave in 2016 would also not vote to rejoin."

Sillars, when asked the consequences of backing a second EU referendum would be for the SNP at the next Holyrood election, said: "We'd lose."

He said the SNP was already at risk of losing seats to Labour. Sillars added: "If we had a referendum on going back into the EU they'd lose. It would be a dreadful mistake. People would lose confidence in their judgement. We are already in danger from Labour anyway."