UK citizens travelling from Northern Ireland to the rest of the UK could be subjected to border control checks in the event of a Brexit, the Prime Minister has suggested.
David Cameron said it would be an alternative option to introducing hard borders between the Republic of Ireland and Northern Ireland if the UK leaves the European Union.
The Government has previously warned that a current free movement agreement between the two nations would be under threat.
Speaking during Prime Minister’s Questions, Mr Cameron said: “If we vote to stay in we know what the situation is. We know that the common travel area works, we know it can continue and everyone can have confidence in that.
“If we were to leave and, as the leave campaigners want make a big issue about our borders, then you’ve got a land border between Britain outside the European Union and the Republic of Ireland inside the European Union.
“Therefore you can only either have new border controls between the Republic and Northern Ireland or, which I would regret hugely, you’d have to have some sort of checks on people as they left Belfast or other parts of Northern Ireland to come to the rest of the United Kingdom.”
He added: “Now we can avoid these risks, there are so many risks here. Risks to our children’s jobs, risks to our economic future, risks to our borders, risks to the unity of the United Kingdom, I say avoid the risks and vote remain next Thursday.”
His warning came after SDLP MP Dr Alisdair McDonnell (Belfast South) insisted a return to customs and passport control checks between Northern Ireland and the Republic would be a “critical economic issue for Northern Ireland’s voters in eight days times”.
Late last month, Irish premier Enda Kenny had warned that border or custom controls “are a possibility” in the event of the UK leaving the EU.
He had said: “Ireland in Europe would still stand by Britain being a member of the Union and of its importance but I have no idea what other European countries, how they would look at Britain whether they decide to leave, given the fact that we’ve come a long way since the 1970s.
Irish citizens living in the UK will have a vote on June 23, alongside British citizens who are living in Ireland.