Former head of MI5: I fear it’s not over in Northern Ireland

Baroness Manningham-Buller said that the UK will be “less safe” if it leaves without a deal and she cited a range of security issues – from terrorism to threats from Russia – which were best dealt with in a “European context”.

She said a no-deal Brexit should be avoided “at all costs”.

“I, as a former member of MI5, am very concerned about the loss of things like the European Arrest Warrant, the loss of access to Europol data and so on,” she told BBC Radio 4.

She voiced particular concern about the impact on the security situation on the island of Ireland: “I am desperately worried. Much of my career was spent working on Provisional IRA, the loyalist terrorist groups in Northern Ireland.

“I can remember when it was thoroughly unpleasant to go through the border and now, if we go back to that, it cuts off the increasing links between Northern Ireland and the Republic which are an important part of the message of the peace process. It will alter dramatically the whole sentiment and politics of Northern Ireland.”

She added: “Throughout the time there has been those who don’t agree with the peace process, who are continuing to mount attacks – generally small-scale. But I don’t think it is over in Northern Ireland. The danger is that it gets much worse again.”