Hundreds of far Left supporters of Jeremy Corbyn will be expelled from Labour within days after its ruling body agreed to ban four groups accused of promoting a “toxic culture” within the party.

The ruling National Executive Committee (NEC) decided on Tuesday to proscribe ‘Resist’ and ‘Labour Against the Witchhunt’, factions which both claim anti-Semitism allegations have been politically motivated.

‘Labour In Exile’, which actively welcomes expelled or suspended members, was banned. Another group, ‘Socialist Appeal’, which describes itself as Marxist, was also proscribed.

HuffPost UK understands that letters of “auto-exclusion”, informing members they have effectively expelled themselves by being members of any of the groups, will be sent by the end of this week.

The NEC approved the proscription with a big majority, insiders said.

Many of the members of the four factions were strong supporters of former leader Corbyn, who remains suspended from the party whip following his reaction to an equalities watchdog finding of institutional anti-Semitism.

A Labour spokeswoman said: “Labour is a broad, welcoming and democratic party and we are committed to ensuring it stays that way.

“The NEC has decided that these organisations are not compatible with Labour’s rules or our aims and values.”

The NEC also agreed to set up a new panel which would look assess whether other fringe groups operating within the party should also be proscribed.

The panel will be drawn from the Organisation Sub-Committee of the NEC, but insiders said that it would not operate as a “Star Chamber” because once it ruled which groups should be banned, expulsion was automatic.

In one concession to critics, it was agreed that the full NEC would have to ratify any decisions by the “Org Sub” committee.

As the lengthy NEC meeting took place, members of the far-Left groups and others – including Corbyn’s brother Piers – demonstrated outside Labour’s HQ in London.

Grassroots group Momentum and Unite the union had both warned that the attempt to “purge” the groups was an act of “machismo” that was unnecessary.

And former shadow chancellor John McDonnell had tweeted that it was a “standard Blairite” tactic to try and show how strong a leader Starmer was.

Corbyn too had expressed strong opposition to the plan.

But one member of the NEC told HuffPost UK that the move was “morally important” because members of the groups had supported those who had been expelled for anti-Semitism.

The Jewish Labour Movement tweeted its approval of the decision.

‘Socialist Appeal’ has also been described as an “entryist” group and some MPs believe its expulsion had echos of the booting out of Militant under Neil Kinnock in the 1980s.

The margins of the proscription votes on the NEC underlined the strength of support Starmer now has on the ruling body, with two-to-one majorities for most of them.

The narrowest vote was to ban ‘Socialist Appeal’, by a margin of 20 votes to 12.

During its nine hour meeting, the NEC also approved preliminary plans to adopt a more independent process for dealing with abuse and harassment on grounds of sex, race and other protected characteristics.

Rules changes will now be drafted and brought before the next NEC meeting ahead of a vote by the annual conference. The NEC also approved a new code of conduct on Islamophobia.

Writing for the LabourList website, party chair Anneliese Dodds said: “By approving a new independent complaints process, the NEC has acted decisively to put our own house in order and show that Labour is – and always will be – the party of equality.”