Labour MPs have overwhelmingly backed a vote of no confidence in Jeremy Corbyn.
The Parliamentary Labour Party voted by 172 to 40 for the motion tabled by veteran backbencher Dame Margaret Hodge, sources said.
The unprecedented vote piles on pressure on the Labour leader following the mass walk-out by Labour front benchers.
However the vote has no formal status under party rules and allies of Mr Corbyn have insisted he has no intention of quitting.
They have said that if his critics want to get rid of him they will have to mount a formal leadership bid – which will ultimately be decided by grassroots activists whose votes swept Mr Corbyn to the leadership last year.