Johnson's ministerial resignation followed that of former Brexit secretary David Davis (who was replaced by fellow Brexit campaigner Dominic Raab) and Steve Baker.
Jeremy Hunt visited the Foreign Office last night.
However, his time at the department was hugely controversial due to his introduction of new contracts for junior doctors.
"Theresa May should call an end to this shambolic farce".
"It is clear this Government can not secure a good deal for Britain".
More than 200 sickened in Del Monte vegetable outbreak Del Monte-branded fresh vegetables have been linked to a parasite that has sickened more than 200 people in the Midwest. A previous major cyclosporiasis outbreak was reported in 2015 , when 546 individuals were infected across 31 states.
Attorney General Jeremy Wright, meanwhile, will be taking up the post of Culture Secretary. Now he will replace Johnson, whose shock resignation on Monday was seen to throw the future of May's government and Brexit negotiations into uncertainty.
Both Mr Johnson and Mr Davis had signed up on Friday to Mrs May's blueprint for Brexit at an all-day summit at Chequers on Friday.
He wrote: "We must have collective responsibility".
"I'd have to be the champion of the policy that I didn't believe in".
The Cabinet minister quit his position, saying "the current trend of policy and tactics" was making it look less and less likely that the government could "deliver on the mandate of the referendum, and on our manifesto commitment to leave the customs union and the Single Market".
Rebuffing claims that her proposals make too many concessions to the EU, May said "this is the right Brexit" and would leave Britain free to make its own laws and trade deals.
In an apparent boost for the embattled PM, chairman of the powerful 1922 Committee, Sir Graham Brady, is said to have confirmed at the meeting now he has not received the 48 letters from MPs that would trigger a no-confidence vote.
Sir Graham refused to say whether he had received any such letters.
Senior backbencher Bernard Jenkin said there had been a "massive haemorrhage of trust" in Mrs May.