Clark is one of a clutch of cabinet ministers, alongside Hammond, justice secretary David Gauke and May's effective deputy David Lidington, who are thought likely to leave government for the backbenches because of Johnson's insistence that he will not appoint cabinet ministers who are opposed to a no-deal Brexit in any circumstances.
United Kingdom leadership front-runner Boris Johnson admitted that he did not know the full details of an worldwide trade rule that he is proposing as a viable plan B for Brexit.
'It's because prime ministers should only make promises they know they can deliver. "A decision was taken - just get on with it - and they are not in that same polarized way that Parliament has been about this issue". "I actually think there's quite a difference between Parliament and the public".
Mr Johnson sidestepped questions about whether he still believed Donald Trump was "stupefyingly ignorant" - in reference to comments he made as London mayor - and came unstuck when grilled on the detail of world trade rules.
Asked whether he would be prepared to delay by days, weeks or months, Hunt replied: "Well, it's not going to be months".
In his BBC interview, Hunt reaffirmed his commitment to leave the European Union without a deal if he was unable to negotiate a new agreement with Brussels on the terms of the UK's withdrawal.
"It is because Parliament may try and take a no deal Brexit off the table altogether and so I think - my commitment is that I think I'm the best person to get a deal and if we get a deal it will be on or around the 31st of October but I can't control what Parliament does and that's why I'm being honest with people about the difficulties".
"We will get a deal by October 31st", Johnson told the BBC during highly-anticipated separate interviews with the leadership rivals, referring to the latest delayed deadline for Britain's departure from the bloc.
"Prime ministers should only make promises they know they can deliver".
"I've always done what I believe to be in the national interest", May said.
But the former foreign secretary insisted his comments in the debate had been "misrepresented" and denied withholding his backing.
'He said that what somebody had relayed to him had been a factor in his resignation, ' Mr Johnson said.
She said she had achieved an "enormous amount" in three years in the job. "That's one of the reasons she has worked incredibly hard to enable the United Kingdom to leave with a deal".
'I think that unfortunately what I said on that TV debate was misrepresented to Kim'. "It had been incredibly frustrating that MPs on either side of the Leave-Remain divide had got so sort of entrenched that they just were not willing to make that compromise that would enable us to get the majority to get this through", May said in a BBC interview in 10 Downing Street on Friday.
"On the one hand, some people who'd always campaigned for Brexit, but didn't vote for the deal because they had a particular vision of Brexit and they were sticking firmly to that vision". Major concluded, "If that were to happen there would be a queue of people who would seek judicial review".