Dominic Grieve has said he’ll quit the Conservative party if Boris Johnson becomes leader.
Speaking on the BBC’s World At One, the MP for Beaconsfield said: "If he was to become leader of the party, I won't be in it.
“It may make good journalism, but it doesn't make a good member of parliament or a good minister."
His comments come after Johnson has faced multiple calls to apologise after a column in the Daily Telegraph where he likened women who wear burqas to “letter boxes” and bank robbers.
- Read more: Imam: 'Boris Johnson's burqa comments are the latest in his legacy of disdain for Islam'
- Read more: Muslim Conservative Chair: Conservative party must investigate Islamophobia
Prime Minister Theresa May has said he should apologise, as has Conservative party chair Brandon Lewis.
Founder and president of the Conservative Muslim Forum Lord Sheikh told the BBC the party should take "severe action" against Mr Johnson.
He said: "Take the whip from him. Why not? He's not a super human being, he's a member of the party.
"The party chairman, the prime minister has the right to take the whip... that's the thing I'd like to see."
Baroness Warsi repeated her calls for an investigation into Islamophobia within the Conservative party in a piece in the Guardian, and noted there had been a 26% rise in hate crimes against Muslims last year, according to figures from monitoring group Tell Mama.
North London imam Ajral Masroor said his comments are the latest in a “legacy” of “disdain” against Islam.