Male MPs will be allowed to speak in the Commons even if they are not wearing a tie, Commons Speaker John Bercow has said.
Mr Bercow outlined a break with the traditional dress code in the Commons chamber by saying it was not essential for MPs to wear a tie providing they are dressed in "business-like attire".
It comes after Liberal Democrat Tom Brake asked a question in the Commons on Wednesday without wearing a tie, which was questioned by Tory MP Peter Bone through a point of order on Thursday.
Responding, Mr Bercow said the "traditional approach" was that male members would wear ties in the chamber.
He added: "I think the general expectation is that members should dress in business-like attire.
"So far as the chair is concerned – I must say to (Mr Bone) I fear this will gravely disquiet him – it seems to me that as long as a member arrives in the House in what might be thought to be business-like attire, the question of whether that member is wearing a tie is not absolutely front and centre stage.
"Am I minded not to call a member simply because that member is not wearing a tie? No.
"I think there has always been some discretion for the chair to decide what is seemly and proper, and members shouldn't behave in a way that is disrespectful of their colleagues or of the institution.
"But do I think it's essential that a member wears a tie? No."
It marks the latest move by Mr Bercow to modernise proceedings in the Commons, having dropped the requirement for clerks to wear wigs earlier this year.
Wellingborough MP Mr Bone had asked the Speaker: "I'm not really one to talk about dress sense, but I noticed yesterday that a member was allowed to ask a question in the chamber without wearing a tie.
"Now, I have no particular view on that, but have the rules on that changed?"
The "Rules of behaviour and courtesies in the House" leaflet issued by the Speaker says that while there is no exact dress code, the convention has been that men are expected to wear a jacket and tie.
The Erskine May parliamentary practice guide also says it remains a custom for male MPs to wear a jacket and tie "but the Speaker has not enforced the practice in all circumstances".