The resignations of two secretaries of state will prompt fears Theresa May could lose more cabinet ministers in the coming hours.
Brexit Secretary Dominic Raab had failed to publicly back the agreement since it was struck earlier this week.
In his resignation letter, he said he cannot support the deal because of the implications for Northern Ireland and also because of the so-called backstop, which would be triggered if no agreement on the future trading relationship can be reached.
Mr Raab wrote:
Work and Pensions Esther McVey, a vocal opponent of the deal, said it was a “risk I cannot be party to” – and reportedly had a massive “bust-up” with Mrs May during yesterday’s cabinet meeting.
It follows a vow from Mrs May on the steps of Downing Street that the agreement she has struck is the best the country could hope for.
Mr Raab is understood to have made his views clear during the cabinet meeting in Downing Street, where he called on the prime minister to go back to Brussels and look for better terms.
There were rumours that he might be considering his position overnight but those were denied by his staff.
Their resignations could trigger a chain reaction in other ministers after one of Mrs May’s junior ministers also left the government over the plans. It follows the resignation of Jo Johnson, the former transport minister, last week.
A Brexit backing MP told Sky News that a number of Conservative MPs have now sent letters to the chairman of the party because of their concerns about Brexit, prompting fears that Mrs May could face a vote of no confidence as a result of the agreement.
(c) Sky News 2018: Raab and McVey’s resignations spark a chain reaction