Sir John Major has warned it is "unwise" for Boris Johnson to stay in Downing Street as his successor is chosen as Tories react to the PM's speech with shock.
The former Prime Minister published his letter to Sir Graham Brady, the chairman of the 1922 Committee, which suggested a caretake PM would be in the "national interest".
Mr Johnson acknowledged his resignation will provide "relief" to many people, but his speech has prompted shock and fury amongst many.
The Prime Minister stood outside No10 for seven minutes, expressing his pain and sadness at not being able to convince his party colleagues that he is still the man for the top job.
"But as we’ve seen at Westminster the herd instinct is powerful and when the herd moves it moves, and my friends in politics no one is remotely indispensable," he told the public.
Sir John said: "The proposal for the Prime Minister to remain in Office - for up to three months - having lost the support of his Cabinet, his Government and his Parliamentary Party is unwise, and may be unsustainable."
He added: "For the overall wellbeing of the country, Mr Johnson should not remain in Downing Street - when he is unable to command the confidence of the House of Commons - for any longer than necessary to effect the smooth transition of Government."
Dominic Cummings swiftly noted the PM's speech puts him in a prime position to create a "betrayal story" as Mr Johnson believes "he's the real victim".
Mr Johnson's former chief aide tweeted: "Blames everyone else. Thinks he's the real victim.
"[This] Sets up betrayal story for future Tory conferences & Telegraph columns. We're all in for a nightmare if he's allowed to squat."
A Tory party source described Mr Johnson's speech as a "bitter" parting shot to the Conservative Party, adding: "It's quite a skill to make a resignation speech sound like an acceptance speech."
A senior Tory MP noted the horror in the Parliamentary tea room, as Mr Johnson called out the "herd", with another describing plans to "get drunk" as it almost seemed impossible to push Mr Johnson out of office.
Tory MP Robert Largan, who was elected in 2019 when Mr Johnson won the huge majority, refused to back Sir John's comments.
But he did express his support for Tom Tugendhat to become the next leader.
"There isn’t really a constitutional mechanism to remove a prime minister, beyond replacing them as leader of the Conservative Party.
“Any decent prime minister would not want to put the Queen into a position where she is dragged into party politics.”
