Just 48 hours ago, the former Vote Leave leader's position was that while May's customs plan, which would keep us bound by European Union rules in perpetuity, was a "turd", he was still willing to sell it.
Former Ukip leader Nigel Farage welcomed Mr Johnson's decision on Twitter, saying: "Bravo Boris Johnson". He attacks May's plans in terms that, one imagines, were sharpened after No10 purposefully made a statement about his resignation before he had published his own.
The Cabinet Secretary is effectively Mrs May's deputy and has previously held the position of Europe Minister in the Foreign Office.
Hunt's post of health secretary has been taken over by culture, media and sport secretary Matt Hancock, as May struggled to keep control of dissenting voices within her top team.
Even so, when May appeared in parliament on Monday afternoon, she didn't look like a woman who was facing an existential crisis. He tweeted the Prime Minister "doesn't have a majority for it and there's no reason why we'd vote for a hard Brexit for services".
Two Conservative lawmakers, Maria Caulfield and Ben Bradley, quit as vice-chairs of the party on Tuesday over opposition to May's proposals.
She earlier faced her critics at a packed meeting of backbench Conservative MPs, many of whom share Mr Johnson's concerns about her Brexit stance.
But her administration was thrown into disarray within 48 hours, as first Mr Davis and then Mr Johnson said that they could not commit themselves to promote the plans under the doctrine of collective responsibility.
The Chequers plan involves the creation of a "UK-EU free trade area" for goods, governed by a "common rulebook".
While the Irish government welcomed Friday's agreement, they said "a lot of work" remains, "particularly from the British side".More news: Donald Trump still pondering Supreme Court pick as big reveal nears
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"I like Boris Johnson, I've always liked him".
Nadine Dorries, the outspoken Bedfordshire MP, said: "I think that we in this room, while being reasonable, need to feel some steel in our spines".
"When he says the Brexit dream is dying, he's really talking about the perspective he had on Brexit, but in my view that was never a live possibility in any instance".
Mrs Rudd's public slapdown came after Mr Johnson, who is widely regarded to have ambitions to become prime minister, penned a lengthy article for the Daily Telegraph that laid out his Brexit blueprint.
Mrs May continues to insist that "no deal is better than a bad deal" and has ordered preparations to be stepped up, but there is little doubt that many within Government view the prospect of quitting the European Union next March without any agreement as deeply unattractive.
Mr Johnson plunged the Government into crisis after he announced he was quitting with a scathing denunciation of her Brexit plans, saying they would leave the United Kingdom a "colony" of the European Union. The EU says it will respond once it has seen the details.
Instead, he said that if voters in his marginal constituency of Mansfield - a rare Tory gain in 2017 - believed the government was not delivering "Brexit in spirit as well as in name, then we are handing Jeremy Corbyn the keys to Number 10".
The European Commission declined to comment on Mr Davis's exit but Donald Tusk, the president of the European Council, said he hoped a change in faces might lead to a change in policy.
But the leader of the Scottish Conservatives Ruth Davidson said Mrs May was "correct to accept the Foreign Secretary's resignation".