Angela Merkel’s warning to UK: David Cameron is moving close to the point of no return

Angela Merkel's warning to David Cameron that she would prefer to see the UK leave the EU than allow it to undermine the core value of the free movement of people is important and timely, whether intended to be public or not. Mr Cameron has been playing a dangerous game of brinkmanship with EU renegotiation to placate his bankbenchers and out-sceptic Ukip. And his repeated insistence that he has enthusiastic but silent allies in European capitals for his crusade has been central to his bluster.

But if the German chancellor, and, indeed, one suspects, Dublin, have been quietly cautioning fellow member states about the dangers of “Brexit” and the need, if possible, to assist Cameron’s delicate political position with concessions, they have clearly become alarmed by his apparent insensitivity to the realistic limits to such concessions and by the false expectations he is raising. An insensitivity which takes support for granted and begins to put potential allies in political difficulty.

Der Spiegel reports that the chancellor believes Mr Cameron is taking the UK to "the point of no return" with demands to curb immigration from fellow member states. Such demands, which go well beyond "welfare tourism" reforms on which a deal might be possible, threaten to undermine the single market, as former Tory minister, and, increasingly, the party's lone advocate of European integration, Kenneth Clarke, despairingly warned on Sunday . "It's the basis of any serious single market. The Norwegians, who Eurosceptics admire, they favour the free movement of labour . . ."

From an Irish perspective the UK insistence on new immigration controls as its red-line renegotiation issue would also be the worst possible issue on which a “Brexit” could hinge. New post-membership barriers to migrants would raise the prospect of the restoration of border controls at Newry on people and trade. Ireland’s traditional common travel area with the UK could also be called into question.