BREXIT has “radically” changed the independence debate and would mean a “range of checks” at the border with England if Scotland rejoined the EU, a new report warns.

It also says Brexit means Scotland would be required to sign up to the euro in the EU, as it would no longer stand a chance of inheriting the UK’s opt-out.

A new paper by Dr Kirsty Hughes, the director of the Scottish Centre on European Relations, says Brexit would also have new implications for fishing, the services sector and free movement if Scotland were to become independent.

Nicola Sturgeon has said she wants a second referendum on independence this year, and for Scotland to rejoin the EU after a Yes vote to avoid the economic damage of Brexit.

However Boris Johnson has refused to grant Holyrood the power to hold Indyref2, and the SNP is now setting its sights on winning an overall majority at the 2021 Holyrood election.

A new panelbase poll yesterday put Yes on 52 per cent.

Donald Tusk, the former president of the EU Council, said on Sunday that there was “empathy” among the remaining 26 EU nations for Scotland, given its 62-38 vote to Remain.

However an independent Scotland would not be automatically admitted as an EU member, and would have to go through an accession process, he said.

Dr Hughes said that accession process would depend on how long an independent Scotland had been part of a post-Brexit UK and diverged from EU rules.

However it is the Scottish-English border which is would be most affected by a combination of Brexit and independence, she says, as it could become a new land border with the EU.

She said: “The biggest change compared to the debates in 2014 surround the border questions. If an independent Scotland were in the EU, then Scotland’s border with the rest of the UK would be an external border of the European Union.”

She said that if Boris Johnson succeeding in getting a Canada-style free trade deal with the EU, “the Anglo-Scottish border would be both a regulatory and a customs border”.

She said: “While the Brexit debate has seen much time spent discussing how to minimise such checks or move them away from the border, it is clear there will indeed be a range of checks needed at the ScotlandUK borders.

“There will be the Scotland-England land border that may require regulatory and customs checks. Then there would be a different sea and air border between Scotland and Northern Ireland - softer than the one with England and Wales perhaps - since Northern Ireland would be de facto in the EU’s customs union and in its single market for goods.

“There will also be considerable challenges around services.

“If a UK-EU free trade deal can be negotiated by the end of 2020, it is not expected to include services. The shape of any future deals on services, transport and various security issues may take considerably longer. So, again, there would potentially be barriers between the rest of the UK and Scotland in the services sector as a result.”

She said if Scotland chose not to join the EU, as SNP MSP Alex Neil has suggested, but went into the looser European Economic Area like Norway, it would cause other problems.

“It would be in the EU’s single market but not in its customs union. It would therefore be free to strike its own trade deal with the rest of the UK.

“The upsides would mean less, but potentially still substantial, friction in Scotland-rUK trade. “The downsides are clear – there would then be borders and barriers in both directions: regulatory borders with the rest of the UK (not being in the EU single market) and customs borders, as Norway faces, with the EU. Any serious discussion would need in-depth economic analysis of the static and dynamic benefits of these different options.”

She concluded: “If, in the end, an independent Scotland negotiated its way back into the EU, it would find itself part, with the other EU member states, of whatever UK-EU trade and security relationship had already been negotiated. It’s clear that, compared to the debate in 2014, Brexit radically changes, in many ways, the implications of independence in the EU.”

However Dr Hughes also said there had been a political shift in Scotland’s favour because of Brexit, with “more openness to the possibility that Scotland could become independent and apply to re-join the EU”.

She said: “Certainly, member states with concerns around secession – including, but not only, Spain – would want to be reassured that any independence referendum was constitutionally and legally valid.

“But, with the UK no longer a member state, and with the ill-will generated by the whole Brexit process, Scotland as a proEuropean, remain-voting country is now seen by EU member states (and indeed by EU officials) in a much more positive light.”

The paper is part of a new report, Brexit and the Union, produced by Edinburgh University’s Centre on Constitutional Change.

Pamela Nash, chief executive of Scotland in Union, said: “This confirms there is a high risk of a hard border with England if Scotland leaves the UK.

“With 60 per cent of our exports going to the rest of the UK, putting up barriers would jeopardise our economy and jobs, particularly under the SNP’s plan to scrap the pound.

“Nicola Sturgeon’s inward-looking and negative vision for Scotland’s future would also lead to a barrier between friends, families and neighbours for the first time in centuries.

“The positive future for Scotland based on solidarity and economic growth is to remain in the UK.”

Meanwhile, it has emerged that a light show projected on the European Commission building in Brussels about Scotland and Europe on Brexit night was paid for by the SNP, not put on by the Commission.

The First Minister had tweeted a picture of the "Scotland Loves Europe" display with the message: "The EU Commission building in Brussels tonight (and if you look carefully you’ll see that they do appear to have left a light on for us!)".

However the brief show on the Berlaymont building was put on by Edinburgh-based Double Take Projections as a party stunt.