LONDON — Former British Foreign Minister Boris Johnson will be investigated for a possible breach of the Conservative Party’s code of conduct after making comments about Muslim women who wear burqas, a party source said on Thursday.

The source said a number of complaints had been received and would be considered by an independent panel.

A spokesman for the party declined to confirm the investigation. “The code of conduct process is strictly confidential,” he said in a statement.

Johnson wrote in The Daily Telegraph this week that Denmark was wrong to ban the burqa, a head-to-toe cloak which conceals the face with a mesh or is worn in conjunction with the niqab — a face veil that leaves only the eyes exposed.

But Johnson, who resigned last month over the government’s Brexit plans, also said the robe was oppressive, ridiculous and made women look like letter boxes and bank robbers, prompting an outcry from other politicians and British Muslim groups.

The Conservative party’s website says suspension of membership or expulsion from the party are among the ultimate options open to its board on conclusion of a code of conduct investigation.

It comes as a watchdog which advises ex-ministers on taking new jobs ruled that Johnson broke ministerial rules by taking up his weekly column at the Telegraph without consulting it first.

The Conservative Party has been accused of not doing enough to tackle anti-Muslim prejudice in its ranks, despite an initiative to boost tolerance and diversity.

The party’s code of conduct states that Tory officials and elected representatives must “lead by example to encourage and foster respect and tolerance” and not “use their position to bully, abuse, victimize, harass or unlawfully discriminate against others”.

Conservative Party chairman Brandon Lewis and leader Theresa May have both called on Johnson to apologize for his comments.

The founder of the Conservative Muslim Forum, Lord Sheikh, has written to Lewis demanding “serious action”, while former attorney general Dominic Grieve said he would quit the party if Johnson became prime minister.

A hundred Muslim women who wear the niqab or burka have signed a letter to Lewis, calling on him to withdraw the Conservative whip from Johnson and launch an independent inquiry into Islamophobia in the party.

“We are not forced to make these clothing choices, nor are we oppressed,” the women write in their letter, which has been issued to the media by the Muslim Council of Britain.

They say Johnson’s words will “inflame tensions in a way that makes it easier for bigots to justify hate crimes against us”. — Agencies