What happens to politicians who say 'I'm not a quitter'?
In a show of defiance, Theresa May has told her critics: "I am not a quitter." It's a phrase much loved by football managers facing the sack but politicians have used it a lot too, with decidedly mixed results.
Perhaps the most famous non-quitter of them all. In 2001, New Labour's "prince of darkness" was seething with indignation at twice being ejected from Tony Blair's cabinet.
It all came boiling over in one extraordinary moment at his general election count.
"It was said that I was facing political ruin," said the newly re-elected Hartlepool MP, his voice straining with emotion.
"My career in tatters, apparently never to be part of the political living again."
"Well, they underestimated Hartlepool. And they underestimated me. Because I am fighter and not a quitter!"
Mandelson's jaw-jutting, eyes-blazing cry of defiance drew ridicule from some but it worked like a charm.
He did quit as an MP two years later - but only so he could be rehabilitated as a European Commissioner, and then, in one of the biggest comebacks in UK political history, as Gordon Brown's second-in-command and a member of the House of Lords. Others have had less luck with the phrase...
Iain Duncan Smith
IDS may hold the record for the shortest period between saying "I'm not a quitter" and quitting. The then Tory leader told his critics exactly what sort of character they were dealing with on the morning of 29 October 2003.
"I'm not a quitter," he declared ahead of a confidence vote by his MPs. By 7pm he was gone.
The disgraced US president first uttered the phrase in a speech in 1952, when he denied accusations he had abused a political expenses fund, in a groundbreaking televised address. It worked - and he was able to keep his place as Eisenhower's running mate.
He reached for it again 22 years later in another televised speech, announcing his resignation as president over the Watergate scandal.
"I've never been a quitter," he told the American people, before proving himself wrong.
"George is not a quitter. Nobody is going to back him into a corner," Mr Osborne's constituency agent told the Daily Mirror on the Sunday after the EU referendum.
Theresa May didn't seem overly concerned about Mr Osborne's proud non-quitter status, however, and promptly fired him as chancellor. He stood down as Tatton MP 10 months after that.
"Brits don't quit - we get involved, we take a lead, we make a difference, we get things done," said David Cameron in the run-up to June 2016's EU referendum.
But he turned out to be one Brit who did quit - on the morning after losing the referendum, despite earlier insisting that he would stay in office whatever the result.
Mr Brown never uttered the immortal phrase.
But he had it thrown at him by his great political friend Tony Blair, who according to a book by Sky News political editor Adam Boulton, thought Mr Brown would stand down before the 2010 general election because "history showed Mr Brown to be a quitter not a fighter".
This sly reference to Peter Mandelson's dramatic show of defiance prompted a furious round of denials from Mr Brown.
"When you've set off on a journey, you have got to complete that journey," he said.
His particular journey ended with defeat at the 2010 general election.