The chairman of the Conservative Muslim Forum has said that he will resign from the party if Boris Johnson becomes the next party leader.
Mohammed Amin told talkRADIO’s Alastair Stewart that he “personally” does not trust Mr Johnson.
“I have been a Conservative Party member for 35 years,” he said.
“I have said in writing that if Boris Johnson becomes leader of the Conservative Party I will resign from it.”
He added: “As a private individual, I have endorsed Rory Stewart on Twitter.”
Mr Amin suggested that other Conservative Party members would also leave the party if Mr Johnson became leader.
“It is not only Muslims, there have been other people in the Conservative Party who have said that they will leave the party if he becomes party leader,” he said.
“There are fundamental issues of trust, integrity and honesty. If you have a person where you do not trust them when they say things, then they are not fit to be party leader.”
In December last year the former foreign secretary was cleared of breaking the Conservatives’ code of conduct with comments he made about women wearing burkas.
He had written that they looked liked "letter boxes" or "bank robbers" in a Telegraph column in which he argued against a ban on full-face veils.
Mr Amin said that he was not “convinced” over the panel’s ruling.
“I am not convinced that the panel properly distinguished between a person’s freedom of speech as an individual and behaviour unbecoming of a Conservative Party member,” he said.
However, Mr Amin said he did not believe the Conservative leadership was “anti-Muslim”.
“What we have done is get ourselves into this mess by not giving it sufficient care or attention,” he added.
“Nobody likes washing their dirty linen in public. There was a hope that if you dealt with low-level anti-Muslim behaviour then it would go away. It has not done.”