David Davis has written to the Prime Minister warning that her plan for Brexit to be presented to the Cabinet at Chequers on Friday is unworkable.

The Telegraph can reveal the Brexit Secretary has sent a letter, setting out his opposition to Theresa May's so-called "third way" plan, amid concerns the EU will reject it out of hand.

In the last-ditch letter, he says the compromise plan the Prime Minister intends to present will fail because it is simply a customs partnership with some additional technological elements.

The letter expresses fears that the EU has already rejected the idea of allowing a third-party country, as Britain will be after Brexit, to police its borders and that discussing such an option is a waste of time, sources told this newspaper.

Mr Davis is understood to be frustrated that Mrs May and her chief negotiator Olly Robbins are refusing to acknowledge the EU's position, setting up the UK to fail.

A Department for Exiting the European Union source said: "David Davis is working closely with the Prime Minister ahead of Chequers."