partygate
Lord Geidt accuses the prime minister of making a "mockery" of the ministerial code.
The loss of yet another ethics adviser came just a week after the prime minister's anti-corruption tsar also quit.
Lord Geidt had previously said the PM had a “legitimate question” to answer over whether he breached the ministerial code over partygate.
Brandon Lewis said the people of Great Yarmouth are "in full support of the prime minister".
Tory peer Baroness Morrissey, a pro-Brexit banker, quits Liz Truss-run Foreign Office before being sacked.
Conservative MP Lee Anderson's "witch hunt" accusation follows colleague Adam Holloway claiming the PM was made to "look like Hannibal Lecter".
The prime minister has said he will fight on despite 148 of his own MPs backing a motion of no confidence in his leadership.
"It was really important at all stages that everyone stuck to the rules."
"While Johnson has survived the night, the damage done to his premiership is severe", the former Tory leader wrote.
Adam Holloway makes his point with an iPad on live TV.