Labour has suspended all travel in early September in a move that appears to confirm that Jeremy Corbyn will attempt to bring down the Government within days of MPs returning from summer holidays.
It appears to confirm that Corbyn will table a motion of no confidence in the Government almost immediately after the summer recess.
The earliest such a vote could take place is believed to be September 4th, the day after recess ends.
Should Labour succeed, Mr Johnson is likely to spark a constitutional crisis, with Downing Street sources indicating he will refuse to resign and instead attempt to call a general election after the Brexit deadline of October 31.
Johnson currently has a majority of one after the Conservatives lost the Brecon and Radnorshire by-election.
Several Tory MPs have hit out at the Prime Minister’s plan to bring Britain out of the EU without a deal in October, which could destabilise him further.
Mr Corbyn has scheduled a shadow cabinet away day on September 2, during which he is expected to outline Labour’s plans for ousting Mr Johnson and seizing power.