Suzanne Breen: The writing's on the wall... May's refusal to read it is what's damning
Theresa May's tenacity and battling qualities have won her admiration even among political foes. But yesterday was far from the Prime Minister's finest hour.
She was akin to the Grand Old Duke of York - except she only marched her troops halfway up the hill before she led them down again.
And boy, did she make them look like eejits. Cabinet ministers and Government spokespersons were insisting all morning that the vote on the Prime Minister's Brexit deal was going ahead.
"Definite, 100%," Environment Secretary Michael Gove told Radio Four. Scottish Secretary David Mundell was equally certain.
A lot of people were made to look ridiculous by Mrs May's 11th-hour-and-59th-minute U-turn.
She is hardly over-run with friends and political allies as it is. She cannot afford to alienate those she retains by treating them this way. Whatever loyalty she commands in Tory ranks is surely ebbing away as a result of yesterday's fiasco.
This was a monumental mess created by the Prime Minister herself and it will damage her immensely among those who until now have respected her grit.
She is running the risk of losing the loyalty of the colleagues who have stood with her through thick and thin until now.
Last week, despite the odds, she was confident and chirpy as she opened the debate on her Brexit deal at Westminster. Yesterday, she wasn't crumbling but she did look like a woman under pressure as she faced MPs.
Labour's David Lammy called her a coward. "Does she appreciate that other prime ministers under pressure did not delay their legislation?
"Margaret Thatcher didn't delay the poll tax, Tony Blair didn't delay the Iraq War decision, John Major didn't delay Maastricht," he said. That will have hurt.
Fellow MP Dennis Skinner was equally scathing. "Mrs Thatcher had a word for it, what she's done today, F-R-I-T, she's frit," he said, referencing the term the Iron Lady used for frightened political opponents.
Mrs May had no choice but to command a retreat in the House of Commons yesterday.
Had she not done so, the scale of her defeat in the vote would likely have resulted in her political obituary.
But the writing was on the wall for her deal for weeks, and her refusal to read it is what's damning.
She is now going back to Brussels to try to do what she has spent the past month telling everybody was impossible - renegotiate the deal.
But she is truly deluded if she believes the DUP and Tory rebels will be won over by verbal reassurances or political statements regarding the backstop. Trust in Theresa May is non-existent. Without changes to the legal text, it's impossible to see this deal getting through Parliament.
If, as predicted, the EU sticks to its position that the backstop won't be binned, a way forward is very hard to envisage.
Westminster sources don't believe the Prime Minister will bring anything back to MPs this side of Christmas. The ultimate deadline for any vote is January 21.
The Liberal Democrats, SNP and an increasing number of backbench Labour MPs are calling on Jeremy Corbyn to propose a vote of no confidence in Mrs May.
But any such move seems doomed to failure as neither the DUP nor Tory rebels have a desire to bring down the Government.
The danger for the Prime Minister is that yesterday's shambles will lead to more Tory MPs submitting letters of no confidence in her and triggering a leadership contest.
Of course, the men in grey suits could come calling regardless if they decide that she is just too damaged to continue with any credibility.
Boris Johnson remains the bookies' favourite to succeed her, with former Brexit Secretary Dominic Raab a serious challenger.
But for now the Prime Minister is still hanging on - by her fingertips.