SNP 'downplaying significance of border challenge'

This would affect several main roads in the region that cross the border.

These include the A1 north of Berwick, the A6105 a few miles to the west, the A697 at Coldstream, the A68 at Carter Bar.

The UK in a Changing Europe report was written by Professor Nicola McEwen of Edinburgh University and Professor Katy Hayward of Queen's University Belfast.

It says the main trunk roads between England and Scotland would need some form of border control and inspection facilities, likely with "red" or "green" lanes for vehicles with goods to declare or not.

If Scotland voted for independence, First Minister Nicola Sturgeon has stated a key objective would be to rejoin the European Union.

She said last year that Scotland would comply with all EU rules if Scotland joined the bloc. And she would try to negotiate arrangements to keep free trade flowing with England.

During an online panel discussion of the report, Prof McEwen said: "I think there is downplaying on the part of the SNP about the significance of the border challenge. In some ways it's not a problem of their making, it's not a problem that they wanted - because they'd much rather the rest of the UK at the time of independence was also within the EU or in the single market. But nonetheless it is a problem that would have to be faced."

Prof Hayward said: "When we imagine a hard border people tend to immediately envisage walls and fences. But the opposite of a hard border is not an invisible one but an open one. Put simply, moving something across a hard border requires overcoming more hurdles than across a softer one.

"These hurdles most obviously take the form of border controls. These include passport controls to manage the flow of people, safety and security declarations to help authorities assess risk prior to arrival, customs facilitations to prevent smuggling and ensuring duties are paid and regulatory controls on standards of goods and services.

"In the case of an independent Scotland in the EU, we do not envisage passport controls at the Scottish-English border, as we expect that an independent Scotland would remain within the Common Travel Area.

"Trade across the border, however, would be subject to the terms of Trade and Cooperation Agreement negotiated between the EU and the UK. This would mean controls of the type we currently see on EU trade with Britain. However, trade for Scotland with the EU would become easier, as would trade with Northern Ireland.”

Recent opinion polls suggest Scotland is evenly split on the idea of independence.

A Scottish Government spokesperson told the Border Telegraph: “The UK in a Changing Europe think tank has published an extensive paper examining the issue of borders after Scottish independence.

“This report shows that Scotland can be a member of the EU and European Single Market, which is around seven times larger than the UK market alone, and also argues that Scotland’s citizens would be likely to continue to able to enjoy freedom of movement across the UK and Ireland.

“Brexit has created new trade borders with 31 countries outside the UK, as well as a border with Northern Ireland – and if Scotland was an independent member of the EU, which this government believes is its best future, it would see an end to those borders.

“Scotland is also currently part of the Common Travel Area, a longstanding arrangement between the UK, Crown Dependencies and Ireland, which long predates the EU.

“The report says any future independence prospectus must meet the challenge ‘that Brexit has presented’ – including border arrangements. The Scottish Government will do so, as we renew the case put before the people in 2014.”