The chairman of the Conservative Muslim Forum has compared Boris Johnson to Adolf Hitler in an attack on the leadership frontrunner.
Mohammed Amin dismissed Mr Johnson’s popularity among MPs, saying “there are many horrible people who have been popular.”
“A lot of Germans thought that Hitler was the right man for them,” he said.
“The test is, is this person sufficiently moral to be Prime Minister, and I believe he fails that test.”
Mr Amin made some efforts to soften the comparison, saying he was “not saying Boris Johnson wants to send people to the gas chamber”.
“We don't expect our politicians, our Prime Ministers, to be saints. But we do require a basic level of morality and integrity,” he added.
In May, Mr Amin told talkRADIO’s Alastair Stewart that he would resign from the party if Mr Johnson became Prime Minister.
“I have said in writing that if Boris Johnson becomes leader of the Conservative Party I will resign from it,” he said.
In August last year, Mr Johnson faced heavy criticism for saying women in burkas looked like “letter boxes” or “bank robbers”.
However, he remains the frontrunner in the leadership contest - and the bookies' favourite - securing 114 votes in the first ballot.
Mr Amin is backing Rory Stewart in the leadership race.