Opposition MSPs have claimed the rest of the UK may put up border points should an independent Scottish Government not fall into line with Westminster immigration policy.
Alex Salmond has dropped hints over the past week that he would seek to make the country more open to immigrants to boost the tax-paying population in the event of a Yes vote next September.
During First Minister’s Questions on Thursday he said Scotland’s age structure could be changed “by not kicking out, as the Border Agency does, the many skilled young people who come to study at our universities and desperately want to work either for a time or permanently in Scotland”.
A spokesman for the First Minister later denied independence would involve any border posts to check people coming in and out of the country due to an immigration policy that vastly differed from Westminster after independence.
However, when quizzed on what actions politicians south of the border might take in the event of Scotland adapting a much more relaxed immigration system, he said: “You have to speak to the UK Government about what their policies are post-independence. That’s one for them to address, not us.
“You can look around Europe, and these islands as well you’ve a common travel area that’s existed between Great Britain Northern Ireland, Republic of Ireland, Channel Islands, Isle of Man, a common travel area which existed long before the European Union.”
He added: “Two different independent countries on the island of Ireland and they don’t have border posts because of the common travel area.”
Ireland currently has a very similar immigration policy to the rest of the UK to stay in the common travel area.
A senior Downing Street source said: “The common travel area only works as long as there is not any significant divergence in immigration policy.”
Scottish Conservative MSP Alex Johnstone said: “The fact is, if a separate Scotland had a different immigration policy the rest of the UK, they would have to act.
“The rest of the UK would see Scotland as a soft point of entry. As a result, that would obviously require some form of border patrol.”
Labour’s shadow immigration minister, David Hanson MP, said: “Alex Salmond just doesn’t get it he won’t take action on low-skilled immigration because he is out of touch with the real effects it is having on people’s wages and jobs in Scotland.
“Communities in Scotland need a Labour government that will stop the exploitation of migrants that leads to the undercutting of local workers.
“A UK Labour government will offer real opportunities for the next generation of Scottish workers by ensuring big companies bringing in people from outside the EU have to also offer an apprenticeship, yet Alex Salmond’s Government has denied 128,000 Scots the training places they need because of his college cuts.
“If the SNP want an independent Scotland to have a radically different immigration policy from the UK then he is raising the real and frightening prospect of border posts between the two nations.”