But the resignation of Sarah Teather – MP for the marginal London seat of Brent Central – was met with a combination of soulsearching and cynicism ahead of next week’s party conference in Glasgow.
She told the Observer that she had become “catastrophically depressed” with Nick Clegg’s support for a crackdown on illegal immigration, adding that she lost her faith in the party after it backed the Conservatives’ £26,000 annual limit on benefits payments.
Teather, who lost her job as a junior education minister in last autumn’s reshuffle, was the youngest MP in the country when she was won a shock by-election victory shortly after the 2003 invasion of Iraq.
She retained the redrawn constituency against the odds in 2010 but the party now faces an uphill battle to defend her 1,345 vote majority at the next election.
But her reputation within the party was hit earlier this year when she chose to vote against the equal marriage bill on religious grounds.