Brexit Secretary Dominic Raab

He was swiftly followed out of the door by Work and Pensions Secretary Esther McVey and junior Brexit minister Suella Braverman. It comes hours after Theresa May announced that she had secured the backing of her cabinet for the deal. Mr Raab - a Leave supporter who was promoted to the cabinet to replace David Davis when he quit in protest at Mrs May's Brexit plans - is among a group of senior ministers thought to be unhappy with the agreement. Mr Raab was closely involved in drafting the 585-page document, which sets out the terms of Britain's departure from the EU.

In his resignation letter, Mr Raab said he could not support it because the regulatory regime proposed for Northern Ireland "presents a very real threat to the integrity of the United Kingdom".

And, he added, the "backstop" arrangements aimed at preventing the return of a hard Irish border would result in the EU "holding a veto over our ability to exit".