British Prime Minister Theresa May has backed calls for Boris Johnson to apologize for saying Muslim women in burkas look like "bank robbers".
The former foreign secretary has so far defied mounting calls for him to apologize for the comments.
May said the remarks "clearly caused offence" as she told him to say sorry.
"What's important is do we believe people should have the right to practice their religion and, in the case of women and the burka and niqab, to choose how they dress.
"I believe women should be able to choose how they dress."
A source close to the former foreign secretary told Sky News it was "ridiculous" his views were being "attacked".
They said Britain must not "fall into the trap of shutting down the debate on serious issues".
"We have to call it out," the source added. "If we fail to speak up for liberal values then we are simply yielding ground to reactionaries and extremists."
The controversy sprung from a piece Johnson wrote for the Daily Telegraph on Monday, in which he argued against following Denmark's lead in banning the burka.