Theresa May's aides have reportedly begun contingency planning for a snap general election to save her premiership after EU leaders rebuffed the Chequers blueprint for Brexit.
Two senior members of her political team responded to her humiliation last week in Salzburg by "war gaming" an autumn vote to win public backing for her plan, according to the Sunday Times.
It comes as Opposition Leader Jeremy Corbyn says he will back a second Brexit referendum if it is supported by the Labour Party conference.
While Labour has never taken the option of a second referendum off the table, Corbyn is facing intense pressure at the conference to fully back the idea.
MPs and union leaders are expected to join a march on the opening day of the conference today to demand a so-called "People's Vote".
Many activists believe with May's plans in disarray following the rejection of her Chequers proposals by EU leaders in Salzburg, the time is now right for Labour to throw its weight behind a fresh ballot.
Corbyn told an eve-of-conference rally in Liverpool: "If this Government can't deliver, then I say to Theresa May: the best way to settle this is to have a general election."
The rally was punctuated by cries of "stop Brexit" from the audience, but most speakers steered clear of the topic, ahead of a conference which Labour wants to focus on housing and workplace rights.