Seven Labour MPs quit the party on Monday, 18 February, saying they no longer had confidence in Mr Corbyn and claiming the party had been "hijacked" by the far left.
One of them, Lucian Berger, said Labour had become institutionally anti-Semitic and she was "embarrassed and ashamed" to stay in the party.
So who are the seven?
At one point he was touted as "Britain's Obama" and was widely expected to become a future leader of the Labour Party.
But the rising star of the Blairite wing of the Labour Party hit the rocks in May 2015 when he quit the race for the leadership only three days after entering it for "personal reasons" which have never truly been revealed.
— Marcus Bernard 🇯🇲 🇮🇳 🇬🇧 (@marcus_bernard) 18 February 2019
Rumours spread about his sexuality but in 2016 he married Alice Sullivan, a fellow lawyer.
Umunna's chances of a career on the front bench of the Labour Party took another nosedive when Corbyn became leader.
Always on the soft right of the party, Umunna was out of kilter with the Corbynistas and increasingly became a lost voice in the wind.
He is a hard-core Remainer too and it was Corbyn's attitude to Brexit perhaps which finally pushed him over the edge.
Umunna has very high regard for his own talents but he would find it extremely hard to retain his seat in Streatham, south London, if he was an independent up against a Labour candidate.
At the heart of the seven splitters' complaints is their claims the Labour Party is "institutionally anti-Semtic".
— Alex Wickham (@alexwickham) 18 February 2019
Luciana Berger, 37, is one of a handful of Jewish Labour MPs and she has been one of the most vocal critics of Corbyn and the party leadership's handling of complaints about anti-Semitism.
Her great-uncle was Manny Shinwell, a minister in Clement Attlee's Labour government in the 1940s, but Berger grew up in a comfortable middle class family in London and went to a private school, Haberdashers' Aske's School for Girls.
— Luciana Berger (@lucianaberger) 17 April 2018
She is the MP for Liverpool Wavertree, a Labour stronghold on Merseyside but her selection in 2010 was shrouded in controversy and Gordon Brown was accused of "parachuting" her in to be the candidate, against the will of local party members.
In 2017 she had a majority of 29,466 but very few of those were voting for her as a person and her chances of retaining the seat against a loyal Labour candidate are miniscule.
Chris Leslie has spent his entire life as a politician.
He was elected to Parliament, as MP for Shipley in West Yorkshire a month before his 25th birthday in 1997 but lost the seat in 2005.
They 7 MPs have only left the @UKLabour and someone in the room is picked up by @BBCNews saying "He's Mad" about @ChukaUmunna 😂 #LabourSplit @ToryFibs @JeremyCorbyn4PM @jeremycorbyn pic.twitter.com/IEf6ewr4BF— Colin Farley #JC4PM2019 (@colinfarley) 18 February 2019
Leslie was a key part of Gordon Brown's unsuccessful campaign for the party leadership in 2007 and returned to Parliament, this time as MP for Nottingham East, in 2010.
For a few months in 2015, he was Shadow Chancellor of the Exchequer until Corbyn came to power and gave the job to his long-time ally John McDonnell.
Leslie has been sulking ever since and has spent the last three years sniping at Corbyn on everything from anti-Semitism to Brexit.
Still only 46, he has nailed his colours to the mast of this new rebel movement but does not retain a personal following in Nottingham and would almost certainly lose the seat to Labour at a General Election.
Angela Smith is MP for Penistone and Stocksbridge, a semi-rural seat on the outskirts of Sheffield which is very marginal and Labour will no doubt fear losing it to the Tories whether or not she runs at the next election.
Smith's career in Parliament — she was elected in 2005 — has been fairly unremarkable.
Her biggest claim to fame is when she tried to prevent the Daily Telegraph exposing her expenses in 2009.
She failed and the paper published lurid details about how she spent £11,000 setting up and furnishing a second home in London.
Mike Gapes, 66, has been MP for Ilford South in east London since 1992.
He has a whopping 31,647 majority but would almost certainly lose his seat to a Labour candidate.
— Mike Gapes (@MikeGapes) 18 February 2019
Gapes is currently chair of the Foreign Affairs Select Committee and is a long-time supporter of the Kurdish cause.
He has also been one of the strongest Remainer voices in the Labour Party and in December 2017 made a speech in the House of Commons — which was much parodied — in which he said withdrawal from the European Union would jeopardise production of Bailey's liqueur.
Last month he tweeted: "Apparently Corbyn is prepared to hold talks with Hamas, Hezbollah, Assad and Iran without preconditions. But not with the UK Prime Minister. Why?"
Gavin Shuker, 37, is a former pastor with the City Life Church in Luton, and has been MP for Luton South since 2010.
Always on the right of the Labour Party, Shuker signalled his intention to vote for Liz Kendall in May 2015.
— Calum Sherwood (@CalumSSherwood) 18 February 2019
He has been a long-term critic of Corbyn's leadership and in September 2018 Luton South Labour Party passed a vote of no confidence in him.
At the last election, he had a majority of 13,000 but if he stands against a Labour candidate it may split the vote and allow in a Conservative.
Ann Coffey was a key player in the failed coup in 2016 which sought to bring down Corbyn after the Brexit referendum.
— Hannah Al-Othman (@HannahAlOthman) 18 February 2019
Coffey, 72, has been MP for Stockport since 1992 but would almost be forced into retirement if there was a General Election and she was up against a Labour candidate.