British MPs delivered a first tie in a Commons vote since 1993 over a proposal seeking to allow a third round of indicative votes on Brexit alternatives.
They voted by 310 to 310 on Labour MP Hilary Benn's amendment, with Speaker John Bercow casting his vote, in line with precedent, with the noes.
This meant Mr Benn's amendment was defeated by 311 votes to 310, majority one.
Mr Benn's amendment was connected to a motion outlining the timetable for the latest backbench takeover of the Commons agenda.
His proposal sought further Brexit indicative votes on Monday April 8.
Explaining his decision Mr Bercow said: “In accordance with precedent and on the principle that important decisions should not be taken except by a majority I cast my vote with the noes.
“The noes have it, by casting vote 311 to 310, that is the proper way in which to proceed.”
Conservative former minister Patrick McLoughlin raised a point of order asking for Mr Bercow to explain when this had last happened, to which the Speaker said:
He said that was “pertaining to the Maastricht Treaty Bill”, and his predecessor in the chair Betty Boothroyd cast her vote “in the way that she did against that amendment”.
He added: “And the rationale… for the exercise of the casting vote that is that, as I’ve said, that it is not for the chair to create a majority that doesn’t otherwise exist.”