Boris Johnson is to face a Conservative party investigation by an independent panel following complaints over his comments about burkas.
It will look at whether the former British foreign secretary breached the party's code of conduct.
It follows a column by Mr Johnson published in the Telegraph newspaper on Monday, in which the MP claimed women wearing the garment look like 'letter boxes' and 'bank robbers'.
His comments were in response to the recently introduced burka and niqab ban in Denmark - although Mr Johnson suggested a total ban 'is not the answer'.
However, the comparisons in the article have caused widespread controversy in the UK, with some senior Conservatives - including party chairman Brandon Lewis - asking Mr Johnson to apologise.
I agree with @AlistairBurtUK. I have asked @BorisJohnson to apologise. https://t.co/RFExXO4LOR
— Brandon Lewis (@BrandonLewis) August 7, 2018
Theresa May backed the calls for an apology, saying the remarks "clearly caused offence".
If found in breach of the Conservative code of conduct, members face sanctions up to "suspension of membership or expulsion from the Party".
The code calls on members to "lead by example" and "not use their position to bully, abuse, victimise, harass or unlawfully discriminate against others".
'Would not reach the bar for a criminal offence'
Earlier, the head of the Metropolitan Police said Mr Johnson did not commit a crime.
Speaking to BBC Asian Network, Cressida Dick said: "Some people have clearly found it offensive.
"I spoke last night to my very experienced officers who deal with hate crime and, although we have not yet received any allegation of such a crime, I can tell you that my preliminary view having spoken to them is that what Mr Johnson said would not reach the bar for a criminal offence. He did not commit a criminal offence."
She added: "I am proud to police in a liberal democracy in which people have the right to express their opinions. What Mr Johnson said, if it is not criminal, is a matter for Mr Johnson and his friends and colleagues and indeed for the Conservative Party."
The controversy comes a month after Mr Johnson - who is seen as a favourite to become the next Conservative leader - resigned from Theresa May's cabinet over the government's Brexit plans.
Additional reporting by IRN
