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.
Mrs May said she was "sorry - and a little surprised" by Mr Johnson's move after his apparent support on Friday.
A YouGov poll recently found that 62% of party members believe he would make a good leader.
Johnson spoke for angry Conservative Brexit-backers in his resignation letter to May when he complained that voters weren't going to get the things he'd promised them when he campaigned to leave the EU.
However, she has support from moderates and there has been no formal challenge to her leadership so far.
In his resignation letter, Bradley inverted May's claim to her MPs on Monday night that failing to fall in behind her plan would risk the Conservatives losing a general election to Labour.
Merkel welcomed the fact that Britain had formulated a position to take into stalled negotiations with the EU.
"But we will do this in a way which will be a smooth and orderly Brexit, a Brexit that protects jobs, protects livelihoods and also meets our commitment to no hard border" between the U.K.'s Northern Ireland and European Union member Ireland, she said.
The mother-of-one from Hampstead, north London, is still in prison in Iran and was told in May she could face a new charge of spreading propaganda. "At least half a dozen people made that point and the prime minister responded, too - what is good for the country is a Conservative government". I think she is strengthened by all of this. May's supporters are now reported to be anxious that more ministers could go and a no-confidence vote could be triggered.
History beckons as France take on Belgium
As for Belgium , their Golden Generation put in one of the best tactical performance of the World Cup to defeat Brazil 2-1. There is then the midfield contest between Pogba and Kevin De Bruyne , who plays for United's city rivals Manchester City.
"May is fighting for her survival", Mujtaba Rahman, a managing director at Eurasia Group, said in a research note.
It comes right before Donald Trump's first visit to Britain as USA president on Friday, as well as the North Atlantic Treaty Organisation summit in Brussels tomorrow.
But the mood in Brussels - especially after hearing this afternoon that Boris Johnson too was gone - is far from blasé. He's been very, very supportive and very nice to me.
"Unfortunately his contribution to the development of bilateral ties with Russian Federation was rather modest, to put it mildly", President Vladimir Putin's spokesman Dmitry Peskov told reporters.
Tory digital minister Matt Hancock - known for his self-branded social networking app - will now takeover Hunt's portfolio as Health Secretary.
"The British government's white paper promised for this week will definitely require closer analysis, which we will especially expect from the team of the European Commission's chief Brexit negotiator, Michel Barnier", Maasikas told the Baltic News Service on Monday, emphasising that the main focus needs to remain on keeping up the unity of the EU's internal market.
Hunt said it was a moment to show that Britain remained a "strong, confident voice in the world".
He went on to explain how the current political turmoil in Britain will work to the EU's advantage in Brexit negotiations.
Tory Brexiteers say the proposals agreed at Friday's meeting of the Cabinet at Chequers are "Brexit in name only".
It is believed that the former foreign secretary has long held ambitions to become PM, but since handing in his ferocious resignation letter on Monday, Johnson has yet to speak publicly on whether he will launch a leadership bid against May.