Treasury minister John Glen and Home Office minister Victoria Atkins are among a group of six ministers to quit Boris Johnson’s government on Wednesday, citing the PM’s “poor judgement” and lack of integrity.

In a scathing resignation letter, Mr Glen said he could “no longer reconcile my commitment to the role” with “the complete lack of confidence I have in your continuing leadership of our country”.

Resigning as justice minister, Ms Atkins told Mr Johnson that “integrity, decency, respect and professionalism” had been “fractured” under his leadership, adding that the party “must be better than this”.

Jo Churchill quit as health minister shortly after Mr Johnson rose to speak at PMQs on Wednesday, attacking the PM’s “jocular, self-serving approach” in her resignation letter.

Stuart Andrew also quit as housing minister during PMQs, saying he could “in all good conscience” tolerate Tory party members still having to “defend the indefensible”.

Earlier on Wednesday, Robin Walker resigned as schools standards minister. And Will Quince quit as children and families minister, saying he could not accept being sent out to defend the PM on television with inaccurate information over the Chris Pincher row.

They are the latest in more than a dozen resignations which have followed the exit of Rishi Sunak and Sajid Javid from cabinet. Mr Glen, a close ally of Mr Sunak, added: “The country deserves better.”

The prime minister faces the biggest leadership crisis of his premiership after his handling of the row over scandal-hit ex-deputy chief whip Mr Pincher sparked outrage.

It comes as a growing number of Tory MPs demand an immediate rule change to the 1922 Committee of backbenchers’ rulebook in order to force Mr Johnson from office.

Simone Hoare, Chris Skidmore and Anthony Browne said they had written to the chair of the committee, Sir Graham Brady, requesting a rule change in order to force a fresh confidence vote in Mr Johnson.

As the steady drip-feed of resignation letters from junior ministers and ministerial aides continued on Wednesday, new Tory MPs declared their opposition to Mr Johnson carrying on at No 10.

Robert Halfon, who has been critical but remained loyal, said: “If there is a vote for a change in leadership, I will now vote for that change”.

Lee Anderson, a 2019 red wall Tory, also questioned the prime minister’s integrity and withdrew support, saying the PM’s decision to give Mr Pincher a job was “not a good appointment”.

Tom Hunt MP also submitted a new letter of no confidence in Mr Johnson to the committee. “Events of the past week have been the last straw that has broken the camel’s back,” he said.

West Dorset MP Chris Loder told BBC Radio 4’s Today programme: “I think he does need to go. I think if he chooses not to, I think the 1922 Committee should act and I certainly would support that approach in the forthcoming 1922 elections.”

However, Mr Johnson has insisted he will not leave No 10. He is understood to have told allies that he is “not going anywhere” and his critics should “calm down”.

Earlier on Wednesday Laura Trott resigned as a parliamentary private secretary, saying trust in politics “has been lost”, while Felicity Buchan also stood down as an aide, calling for “fresh leadership”.

Following PMQs, Selaine Saxby, Claire Coutinho and David Johnston each said they were quitting their posts as PPSs, officials who assist ministers in their role.

Their resignations followed a string of departures from the government on Tuesday evening, led by Mr Sunak and Mr Javid, who delivered broadsides at Mr Johnson as they quit their cabinet posts.