THERESA MAY’s right-hand-man has ruled out a devolved immigration policy for Scotland.

Cabinet Office Minister David Lidington said such a system would be “too difficult” without internal passports.

However, Mr Lidington suggested that it may be possible for Scotland, or parts of Scotland, to benefit from special work permits designed to aid specific regions or sectors.

Scotland’s population hit another historic high last year, according to figures released on Thursday. But this was only because of net immigration, half from the rest of the UK and half from the rest of the world. And number-crunchers from the National Records of Scotland warned the pace of growth was slowing down.

Asked if this trend justified the SNP’s call for new powers, Mr Lidington said: “It is difficult to dissolve immigration powers unless you have some sort of internal passport system, between different parts of the UK. “

That, he said, would be a “major change to the devolution settlement”. Mr Lidington was sceptical about the practicalities of a devolved scheme, comparing it the distribution of refugees within the EU’s Schengen area. He said: “In practice, people, whichever country they are assigned to, if you have them move freely from one country to another well they move to where they wan to, to where they think the conditions to work where the living standards are greatest.”

Mr Lidington added: “The Migration Advisory Committee has repeatedly looked at this question as to whether there needs to be something which is Scottish specific or Wales specific and every time they have come and said the evidence is just not there.”

“It seems to me that if there is evidence that there is a particular need for Scotland, then that evidence can go to the MAC and it can make its recommendations. There is nothing now or after we leave the EU that stops particular provisions being made for particular sectors or even regions of the UK.”

As The Herald revealed in its Beyond Brexit series, experts advising the Scottish government did consider a Scottish “passport” that would allow Scots to live and work on mainland Europe after Brexit and EU nationals to work in Scotland. In effect, the passports would have been special national insurance numbers.