He acknowledged Mr Johnson had made “a really important start” in reforming the culture at Downing Street, including a complete overhaul of senior staff, but alluded to “an awful lot” of anger in his own party.
Pressed on if he had submitted a letter, Mr Penrose replied: “Forgive me, I’m still thinking about that so I’m going to sleep on that. But it’s because it hasn’t put the issue to bed one way or another.
“There is a great deal of concern about whether or not he’s been telling the truth in Parliament, for example. That’s another example of something that hasn’t been answered.
“It could be months, and that’s one of the reasons I’m sounding so angry and frustrated is that I was expecting us to be able to have a crystallised answer now, and we haven’t flipping got it.”
On Thursday night it was reported Philip Dunne, the Conservative MP for Ludlow, said the “benefit of doubt” had been lost by Mr Johnson, yet he stopped short of calling for his resignation.
Three Tory MPs submit letters in one day
Meanwhile Mr Hammond, the MP for Wimbledon since 2005 whose majority is just 628 votes, said he could not “defend the indefensible” and doubted whether Mr Johnson could regain public trust.
“Since December 9, I have been critical of the Prime Minister’s behaviour and the culture that existed in Number 10,” he wrote on his website. “All I can do as a backbencher is speak out and submit a letter.”
Mr Baron, the veteran MP for Basildon and Billericay, said Ms Gray’s report painted a “shameful pattern of misbehaviour” and the “most serious charge against the Prime Minister is that of knowingly misleading Parliament”.
“Having always said I would consider all the available evidence before deciding, I’m afraid the Prime Minister no longer enjoys my support – I can no longer give him the benefit of the doubt.”
In comments first made to the Times, Mr Simmonds, the MP for Ruislip, Northwood and Pinner, said: “It is clear that while the Government and our policies enjoy the confidence of the public, the Prime Minister does not.”
It is currently unknown whether Mr Baron or Mr Simmonds have submitted letters of no confidence to Sir Graham.