THE SNP is on course for an "all-time record performance" in next week's European vote, according to Scotland's leading election expert.

Professor Sir John Curtice said the party was one track to win around 40 per cent of the vote, which would probably translate into three - possibly even four - of Scotland's six MEPs.

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Prof Curtice, of Strathclyde University, said such an outcome would "reset" Scottish politics after previous gains by the Conservatives in the 2017 Holyrood election which were seen a vindication for an anti-indyref2 stance.

Writing in the Scotsman, Prof Curtice said: "If polls of how Scotland will vote in the European elections on 23 May are at all correct, the political mood north of the border could be about to be reset once again.

"The nationalists look set to emerge from the elections as winners with momentum, while the Conservatives could look like sorry losers whose recent revival has been stopped in its tracks."

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He added: "Two polls conducted to date suggest that the SNP are set to win some 40 per cent or so of the vote.

"Not only would that represent an 11-point increase on what was a relatively disappointing performance by the party in the last European elections in 2014, but it would also be an all-time record performance for the party in any Euro-ballot, surpassing the 33 per cent the nationalists won in 1994.

"It would also represent an improvement (of three points) on the party’s performance in 2017. Being able to claim that Scotland has swung back towards the party in the last two years is probably the claim that above all the SNP would like to be able to make after the votes have been counted."

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Prof Curtice stressed that the key strength for the Nationalists was that around two-thirds of the 45% who voted Yes in 2014 intend to vote SNP in next week's European elections.

The party is also popular among Remain voters - although not all SNP supporters want to remain in the EU.

SNP veteran Jim Sillars, who is a longtime critic of the party's pro-EU stance, has said that he faces an "enormous dilemma" over whether to vote SNP next week. He said he is considering abstaining instead.

Prof Curtice said: "SNP seems to be winning the battle for the support of those who voted Remain in the EU referendum, no less than half of whom are in the nationalist camp.

"The party’s support not only for another independence referendum but also a second EU referendum seemingly assures it of a substantial vote on 23 May.

"For the Conservatives, in contrast, the initial Scottish polls of European voting intention have been deeply disturbing. One put the party’s support on 16 per cent, the other on just 10 per cent."