Both sides of the Scottish Independence debate are wrong when it comes to potential controls on the Scottish/English border, according to a leading immigration expert.

Thom Brooks, a professor of law and government at the University of Durham and a Labour Party activist, told IBTimes UK that Unionists and Nationalists are both mistaken when it comes to the implications of an independent Scotland joining the Common Travel Area with the UK and Ireland.

The CTA currently includes the UK, the Republic of Ireland, the Isle of Man, Guernsey and Jersey.

The area, however, is not a free movement zone and border checks can be imposed.

"If Scotland did vote for independence, and it did seek to join the CTA, then I think it is certain that the terms of what it would mean to be in the CTA would change," Brooks explained.

But Brooks argued that the Labour leader Ed Miliband and other unionist politicians have gone too far when arguing that there will inevitably be border controls.

The immigration expert's comments come after Miliband told the Scottish Mail on Sunday that "'if you don't want borders, vote to stay in the United Kingdom".

The Scottish National Party (SNP), part of the Yes Campaign, has ruled out border controls in an independent Scotland.

"Not only does the UK share a common travel area with the Republic of Ireland, which sets its own immigration policy, it is actually deepening it by common visas," said Annabelle Ewing, a nationalist MSP.

But Brooks explained that the SNP's argument is based on a popular misperception.

The academic said that UK citizens do not have to undergo formal immigration checks when they fly back from the Republic of Ireland because of the Ireland Act 1949, not because of CTA rules.

"Shortly after Irish independence, Westminster passed [legislation] that said that Britain was not going to recognise Ireland, for all legislative purposes, as a foreign country," Brooks said.

The consequences of this law is that Republic of Ireland citizens are not considered aliens in the UK.

The comments come after a shock survey from YouGov for The Sunday Times put the Yes Campaign ahead in the opinion polls ahead of the Scottish independence referendum.

The research, released 11 days before the vote, revealed that 51% of respondents intend to vote "Yes", against 49% of people who said they would vote "No".