But as Foreign Secretary in May's government, he was prone to gaffes and criticized for not being on top of his brief. Dominic Raab, the former minister of state for housing and planning, was named the new Brexit secretary.
"This is a time when the world is looking at us as a country, wondering what type of country we are going to be in a post-Brexit world".More news: The big money behind Trump’s Supreme Court pick
Hardline Brexit backers in the Conservative Party are meeting later Monday to decide on their strategy.
Opposition Labour Party leader Jeremy Corbyn said the government was incapable of delivering Brexit. Leading proponents of Brexit called on her to abandon the deal struck with the Cabinet last Friday at Chequers, her country retreat outside London.
Ministers signed off on a blueprint for a new U.K. -EU "free trade area", with interwoven customs regimes, and identical regulations for industrial and agri-food goods.More news: Croatians who have made their mark in England
With Britain due to leave the 28-nation bloc on March 29, 2019, European Union officials have warned Britain repeatedly that time is running out to seal a deal spelling out the terms of the divorce and a post-split relationship.
Mr Juncker said: "This clearly proves that at Chequers there was clearly a unity of views in the British Cabinet".
But criticism from euroskeptic Tories mounted over the weekend, with many calling for ministers to stand by their principles and make a stand.More news: David Davis quits as Brexit Secretary leaving Theresa May facing a crisis
Appearing on LBC, Davis told host Iain Dale he didn't agree with Johnson's decision to quit. A divorce agreement with the European Union is due to be wrapped up in October, but there are still major obstacles to overcome.