NICOLA Sturgeon needs to hold a second referendum by early 2019 if an independent Scotland wants to move smoothy to European Union membership, according to a leading expert.

Dr Kirsty Hughes, Director of the Scottish Centre on European Relations, explained if a new plebiscite within this timescale resulted in a Yes vote it would give the country two years to become independent before UK left the single market.

She said a successful new plebiscite would then put the First Minister in a position where she could ask the EU to extend a single market transition period for Scotland while engaging in the process for the new independent country to join the bloc.

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Hughes’ intervention comes after EU Council President Donald Tusk yesterday gave the green light to Theresa May for talks to move to a second phase as he announced a transition arrangement between the EU and the UK. Under the guidelines for the agreement, expected to be in place for two years, the UK will be required to follow the rules of single market and be under the jurisdiction of the European Court of Justice.

“There isn’t yet a precise end date for transition but if the roughly two years were to end in early 2021 then if Scotland voted for independence and wanted the smoothest possible transition into EU membership, it would need to have an independence referendum in early-ish 2019,” said Hughes, who is director of the Scottish Centre of European Relations.

“This wouldn’t mean that Scotland would automatically become an EU member state in 2021, as the rest of the UK left. But it would make it much easier, if Scotland were independent by then, to perhaps prolong the transition just for Scotland as it opened accession talks with the EU27 if it was independent in 2021.”

She added the transition period announced by Tusk for the UK “could mean that there is a potentially quite smooth route to EU membership”.

Scotland voted by 62 per cent to remain in the EU and recent opinion polls have indicated support for continued membership exceeds that figure. Following the triggering of Article 50 in March the First Minister set out plans for a new referendum between Autumn 2018 and Spring 2019.

However, after the snap General Election in June and the loss of 21 SNP MPs she put her plans temporarily on hold announcing a “reset” of her proposed timetable. She said she would delay introducing legislation for a referendum, though later said it was still “likely” a referendum would be held by 2021.

Recently, however, there have been hints the First Minister is preparing to take another look at plans for a new vote — indicating last week an independent Scotland should be able to have a soft border with the UK, in line with UK Government thinking on future solutions for the Irish border.

A Scottish Government spokesperson said: “As the First Minister has made clear, we will not seek to introduce the legislation for an independence referendum at this stage. However, once negotiations with the EU are concluded, and when the terms of Brexit are clearer, we will come back to Parliament to set out our judgment on the best way forward.

“In the meantime, we will redouble our efforts to protect Scotland’s interests, including our continued place in the single market, which is vital for jobs, investment and living standards,” she added.