LONDON, United Kingdom (AFP) — British Prime Minister Theresa May’s government imploded on Monday as Foreign Secretary Boris Johnson followed Brexit minister David Davis in resigning over her master plan for Britain’s future outside the EU.

Davis and his deputy dramatically quit overnight over May’s plan to retain strong economic ties with the European Union even after Britain leaves in March next year.

Brexit cheerleader Johnson then delivered a stunning second blow when he also marched out, triggering speculation that May could face an imminent leadership contest.

May’s Brexit plan – agreed by the cabinet on Friday in the hope of unblocking negotiations with Brussels due to resume today – has now cost her two of her top four ministers, throwing her administration and authority into turmoil.

“This afternoon, the prime minister accepted the resignation of Boris Johnson as foreign secretary,” her Downing Street office said in a three-sentence statement.

“His replacement will be announced shortly. The prime minister thanks Boris for his work.”

Johnson criticised the Brexit blueprint in private but has so far refrained from public comment.

Downing Street swiftly appointed eurosceptic housing minister Dominic Raab to Davis’s job, and said May was looking forward to working with him to deliver Britain’s departure from the EU in March.

The resignation of Davis, with a stinging warning that Britain was “giving too much away too easily” in Brexit talks, was a blow to May just days after she declared a truce among her warring ministers.

All eyes are now on the next move by Brexit hardliners in her centre-right Conservative Party.

But the appointment of Raab, a leading Brexit supporter, suggests Tory Brexiteers are divided.

Davis himself said it would be “wrong” if his departure led to a full-fledged rebellion, insisting that “of course” May would survive.

May will address Parliament later to explain her proposal for Britain to adopt EU rules on goods after Brexit, and is also expected to speak to Conservative MPs.

The plan was agreed by cabinet ministers during marathon talks on Friday, where even those wanting a clean break from the EU fell into line.

The deal meant that for the first time since the vote for Brexit in June 2016, Britain has a detailed proposal to take to Brussels, and still hopes to agree a deal by October.