UNREGULATED free movement following Brexit is a “fiction of imagination” and Liam Fox’s comments “illogical and under-researched”, according to an immigration expert.

Professor Alison Phipps, a senior lecturer director of the Graduate School for Arts and Humanities at the University of Glasgow, was responding to the UK International Trade Secretary’s claim that “unregulated free movement of labour” after Brexit would “not keep faith” with the EU referendum result.

Speaking to the Sunday Times, Fox said that border control was one of the reasons the nation voted to leave though insisted the Cabinet had not agreed a deal on immigration after withdrawal from the EU.

“We made it clear that control of our own borders was one of the elements we wanted in the referendum, and unregulated free movement would seem to me not to keep faith with that decision,” he said.

However, that appeared to contradict what others in his own party were saying, as tension in Tory ranks continues to rise.

Chancellor Philip Hammond signalled on Friday there was “broad acceptance” in Cabinet of a wide-ranging, post-Brexit transitional period lasting up to three years, though Fox denies that he has been involved in any Cabinet discussions on extending free movement until 2022.

Hammond’s comments also prompted Tory Brexit minister David Jones to brand the initiative “deeply dangerous”, accusing the Chancellor of “going on manoeuvres” while Prime Minister Theresa May was away on holiday.

Regardless of what the Tories have or haven’t decided amongst themselves, Phipps has called into question the validity or Fox’s arguments.

“All movement of peoples across international borders is subject to regulation including existing EU free movement,” she said. “Unregulated movement is a fiction of imagination and not an existing reality of statehood or citizen rights.

“The UK was never part of the Schengen arrangements so Liam Fox appears to need to improve the accuracy of the briefings he is receiving for the sake of negotiations which by all accounts are in a parlous and precarious state.”

“That a former Ukip leader and ardent Trump supporter [Nigel Farage] has approved Liam Fox’s illogical and under researched comments tells us all we need to know,” she added.

Phipps also rejected ending free movement for UK citizens was something that was tested at the ballot box in June last year, stressing that a wide range of issues were at play.

The SNP’s Minister for UK Negotiations on Scotland’s Place in Europe Mike Russell added that a lack of any transitional period or separate deal for Scotland following Brexit will be “a major threat” to Scotland’s economy.

He warned that immediate restrictions on freedom of movement when the UK leaves the EU demonstrates why Scotland would be better off having control of its own immigration policy.

“A hard Brexit, with restrictions on freedom of movement, would be major threat to Scotland’s economy, jobs and living standards,” he said. “These latest comments further emphasise why there is a wide and growing support for Scotland to have responsibility for its own immigration policy.

“Our clear position is that we want to secure a way forward that allows Scotland to remain within the single market — benefitting from the free movement of people,” he added.