Theresa May has been appealing for help from union chiefs amid signs she faces the biggest Commons defeat ever over her Brexit deal.
The PM is on track to lose by a massive 228 vote margin next Tuesday as Tory Brexiteers and Remainers rebel to join Labour in the division lobbies, according to a BBC analysis.
The biggest previous setback for a government is believed to be by 166 in 1924, when Labour's Ramsay MacDonald was leading a minority administration.
However, in a chink of light for Mrs May two Tory MPs, George Freeman and Trudy Harrison, revealed they are switching sides to support her deal.
At a Downing Street press conference, the Prime Minister insisted 'for those who want to avoid no deal, backing the deal is the right thing to do'.
Speaking alongside her, Japan's PM Shinzo Abe warned Britain against no deal and said the 'world is watching' as MPs wrestle with how to deliver Brexit.
The intervention was slammed by Brexiteers who warned it would prove as damaging to the PM as Barack Obama's endorsement of Remain in 2016.
As efforts step up to turn the tide, No10 also confirmed spoken to Unite chief Len McCluskey - a close ally of Jeremy Corbyn - about how to find a way forward on Brexit.
It will be the first ever meeting between May and McCluskey, according to reports, as the Prime Minister attempts to gain cross party support.
Estimates from the BBC suggest just 206 are going to back her plan - with 433 against.
The PM's spokeswoman confirmed Mrs May has spoken to Mr McCluskey and Tim Roach for the first time since becoming Prime Minister.