Four Labour Parliamentary candidates have been banned from standing by the party's National Executive Committee.
Three are former Labour MPs - including Jeremy Corbyn ally Chris Williamson - and the fourth is Sally Gimson who was selected less than two weeks ago.
Mr Williamson was suspended in an anti-Semitism row and Mrs Gimson is facing claims she says are a "smear campaign" against her.
Meanwhile, Labour has confirmed it is reviewing another candidate.
Zarah Sultana, who apologised for saying she would "celebrate" the deaths of world leaders in 2015 on social media, is being "re-interviewed" by a panel, the party said.
New candidates will be chosen in place of former Derby North MP Mr Williamson, ex-MP for Jarrow Stephen Hepburn, and Roger Godsiff, who was facing a reselection battle in Birmingham Hall Green.
Mr Williamson said on Twitter that he was resigning from the Labour Party "with a heavy heart" after 44 years and will be standing as an independent candidate in Derby North.
It comes as Conservative Alun Cairns resigned from the cabinet over claims he knew about a former aide's role in the "sabotage" of a rape trial.
Mr Cairns still intends to stand as a Tory candidate in the general election.
Labour's ruling National Executive Committee (NEC) has not made a final decision on whether Keith Vaz can stand for the party, the BBC understands.
The former Leicester East MP was last week suspended from the House of Commons for six months by a standards watchdog.
Mr Vaz "disregarded" the law by "expressing a willingness" to help buy cocaine for male prostitutes, the Commons standards commission said in a scathing report.
Mr Vaz was re-selected as Labour's candidate in Leicester East, a seat he has represented for 32 years, a few weeks before the publication of the standards report.
If he was re-elected on 12 December, he would take up his seat until parliament voted again on a potential suspension, which ended with the conclusion of the previous parliament- and he could face a recall petition, giving voters a chance to remove him.
Mr Vaz did not make any comment on his suspension, but a spokesman said he was receiving treatment for a serious mental health condition.
Labour's ruling NEC ditched Chris Williamson because the disciplinary case against him hadn't concluded. That meant he was still suspended and therefore ineligible to be a candidate.
But this apparently bureaucratic formulation somewhat understates the political sensitivities, some on the left want him reinstated because they argue that while he said the party had given too much ground on anti-Semitism, what he said wasn't in itself anti-Semitic.
But others - including some of his fellow left-wingers - wanted him out as they knew opponents would suggest any reinstatement showed a lack of seriousness in addressing anti-Semitism allegations.
Plus I am told many in the Labour leader's office lost patience with Chris Williamson's loose tongue - and tendency to shoot from the hip.
Keith Vaz's fate is less certain. Labour's NEC didn't throw him out - apparently as he is in hospital. Well-placed sources say they hope he stands down voluntarily.
But a rather stranger row might yet overshadow all this.
Sometimes candidates are "parachuted in" by the leadership. Sometimes they are deselected. But it's rare to be selected then deselected in the space of a week
Sally Gimson contested the selection in Bassetlaw where John Mann is standing down - unexpectedly beating a candidate favoured by some in the leadership and by the powerful Unite union.
But the decision of local members was overturned by a panel of Labour's ruling NEC.
Sources cite complaints about Sally Gimson - but from party members in her home constituency in London, not Bassetlaw where the local executive is right behind her.
She has denounced the NEC as a "kangaroo court" acting on "trumped-up charges" and the row could now be settled in the actual courts.
Chris Williamson was suspended by Labour in February after claiming the party had "been too apologetic" in its response to criticism of handling anti-Semitism allegations.
He was reinstated in June but was suspended again after a backlash from MPs, peers and Jewish groups.
Last month, he lost a High Court bid to be reinstated by the party - but the judge also ruled Labour acted unlawfully when it re-opened the disciplinary case against him.
Marie van der Zyl, the president of the Board of Deputies of British Jews, called on Labour to go further after the NEC made what she called the "correct" decision to stop him standing again.
She said: "Labour's leadership must now stop dragging their feet and act immediately to expel from the party this disgraced politician who has baited the Jewish community for far too long."
LGBT school row
Stephen Hepburn was suspended by the Labour Party last month, as it launched an investigation into claims he sexually harassed a female party member in her 20s at a curry house 14 years ago.
Mr Hepburn said he "completely refutes" the allegation.
Roger Godsiff, meanwhile, had been facing a vote of constituency party members over whether he should be allowed to stand again before the NEC stepped in.
The former MP has been at the centre of a row over his support for protesters against LGBT teaching and was formally reprimanded by Labour after he was seen in a video agreeing with the demonstrators.
Correction 7th November 2019: This article originally referred to how, if re-elected, Keith Vaz would not be able to take up his seat until his suspension ends. This has been amended to make clear that he could take up his seat, with the suspension requiring a new vote in the next parliament.