Your Party membership stands at 50,000, Sky News can reveal.
The figure is well short of the 800,000 people who expressed interest when it launched, and it is significantly below the 100,000 to 200,000 insiders hoped would join officially as members following its launch in July.
It puts the Zarah Sultana and Jeremy Corbyn-led party close behind the Liberal Democrats, whose membership has fallen to 60,000.
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While still deemed to be respectable to those involved in the party, the membership update has been taken as a warning that the factional infighting between Ms Sultana and Mr Corbyn has damaged its hopes of immediately building a mass movement.
However, Your Party said it expects membership to increase as more members move over from the "unauthorised" membership portal launched by Ms Sultana on 18 September.
Tensions between the two leaders reached a boiling point when Ms Sultana sent out unauthorised emails encouraging paid membership without Mr Corbyn's consent - while also claiming her actions were the result of being sidelined by a "sexist boys club".
Mr Corbyn is expected to announce the 50,000 figure at a rally in Islington on Monday evening.
He said: "I am excited to announce that 50,000 people have now become members of Your Party.
"This major milestone reflects what Your Party is all about: a mass, democratic movement for change. From local rallies to mass regional assemblies, people up and down the country are coming together to build this party from the ground up.
"This is just the beginning. At the end of this month, we will host our founding conference. This will be the moment that members come together to launch our mass, democratic movement for real change."
Ms Sultana's decision to launch her own membership portal in September culminated in a standoff over the control of £800,000 worth of donations, which has only just been resolved.
The pot of money had been held by an entity called MOU operations - controlled by former Labour MP Beth Winter, former Labour mayor Jamie Driscoll and former South African politician Andrew Feinstein - who have now all quit.
Sky News revealed last week that Ms Sultana now had sole control of the £800,000 and that she has assured Mr Corbyn that the money will be transferred to the party as a whole.
It is understood the money has not yet been transferred in full.
The money collected by MOU in membership fees is not expected to be transferred to Your Party as those who paid are entitled to a refund.
Some 20,000 people signed up to Ms Sultana's portal but Your Party still does not have access to their emails, meaning there is no way of contacting them.
There are concerns within Your Party that the direct beneficiary of the row has been the Greens, led by Zack Polanski, whose membership has more than doubled to 150,000 people.
Following the publication of the figures, Mr Polanski described the Greens as the "only real opposition left in British politics".
Pointing to the threat he also poses to the Labour Party, which has slumped to 17 points in the polls, Mr Polanski said his desire was not to be "disappointed" with Labour but to "replace them".
According to Labour's annual accounts published in August, party membership now stands at 333,235 - down from a peak of 532,046 at the end of 2019, when Mr Corbyn was still Labour leader.
However, Sir Keir Starmer still leads the largest party in the UK.
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As of August this year, the Conservatives were reported to have 123,000 members, while their rivals Reform have 266,172.
In recent weeks, Ms Sultana - who has spoken favourably about some form of electoral pact with the Greens - has sought to draw clearer dividing lines with Mr Polanski.
In a recent interview with Politics Joe, the Coventry South MP described Your Party as "anti-Zionist" and also suggested the UK should leave the military alliance NATO immediately.
Mr Polanski, who is Jewish, has said he is proud of his identity but that he does not describe himself as a Zionist.
He has also taken a more cautious stance on NATO than Ms Sultana, saying that while he supported the UK's eventual withdrawal he was not advocating for it to leave the alliance.
                    
                
(c) Sky News 2025: Jeremy Corbyn reveals the number of people who have joined Your Party
                                            
                                                    
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