The Muslim Council of Britain has urged Theresa May to launch an independent inquiry into Islamophobia in the Conservative party after several MPs supported “dehumanising comments” made by Boris Johnson.

Boris Johnson is leveraging hatred and racism in his desire for power | Rupa Huq Read more

The group’s letter to the prime minister said that the level of political support for the former foreign secretary’s controversial newspaper column about fully-veiled Muslim women had “highlighted the underbelly of Islamophobia” in Tory ranks and demonstrated the need for action.

“Rather than see the bigotry for what it is, we are shocked that a large number of Conservative MPs would seek to back Mr Johnson for his dehumanising comments, ones that mimicked far-right memes and attacked Muslim women,” said the letter, signed by the MCB’s secretary general, Harun Khan.

The group praised May for showing support for Muslims after the Finsbury Park terror attack on worshippers, when she said: “There has been far too much tolerance of extremism in our country over many years – and that means extremism of any kind, including Islamophobia.”

Equality watchdog attacks Boris Johnson's 'inflammatory' remarks Read more

It added: “We are writing to you to continue the leadership you have previously shown, and to urge you to launch an independent and transparent inquiry into Islamophobia within the party and more broadly in society.”

The issue resurfaced a week ago when Johnson compared women wearing the burqa, or niqab, to letter boxes and bank robbers. He has been referred to an internal disciplinary inquiry, which prompted another round of complaints from his allies.

The MCB – which describes itself as “a national representative Muslim umbrella body” with more than 500 organisations affiliated to it, including mosques, charities and schools – complained about an intervention made by the MP Nadine Dorries, in which she supported Johnson. In an interview with Sky News, she said he had made “an accurate description and it was one that many people have used” of a garment that she described as medieval.

Attempts to call for an inquiry had been largely ignored by the party’s chairman, Brandon Lewis, the MCB said. It accused Lewis of “a lack of material response” on previous occasions when it had raised the issue.

Journalists must fight for facts – and ignore Boris Johnson’s tea party | Suzanne Moore Read more

The Conservative party declined to comment or respond when the MCB asked Lewis to act in June. Tory sources briefed that the government had ended contact with the MCB in 2009, when Labour was in power.

The letter also repeated calls for May’s party to initiate a full disciplinary inquiry about Johnson’s comments. Dozens of complaints made against the prominent Brexiter have been examined by an independent assessor who was expected help decide if a full three-person panel should be appointed.

“We are hopeful that the party will not allow any whitewashing of this specific inquiry currently in process. No one should be allowed to victimise minorities with impunity,” the letter said.

Johnson has refused to comment on the row generated by his Telegraph column, telling friends that he believed it was unnecessary to apologise. His latest column, published on Monday, made no reference to the controversy.