A Jewish Labour councillor has quit the party over the leadership's "disgraceful" treatment of Liverpool MP Luciana Berger.
In a scathing letter seen by the JC, Councillor Dany Louise also said the "level of denial" by Jeremy Corbyn supporters over Labour's antisemitism problem "leaves me in despair".
Her resignation comes amid claims that thousands of members are now leaving the party as a result of Mr Corbyn's failure to tackle antisemitism and his policy on Brexit.
The case of Ms Berger, who faced two motions of no confidence from her local party for criticising Mr Corbyn over antisemitism, caused outrage and anger among party supporters. They were later withdrawn.
The JC later revealed the chair of Ms Berger's Constituency Labour Party has promoted Rothschild conspiracy theories on a show broadcast by David Icke.
In a damning message to Mr Corbyn on Tuesday, Labour MP Neil Doyle tweeted members were "leaving in their thousands" while adding:"Antisemitism continues in your name".
I can't make Parliamentary Committee today & as emails are screened I thought I'd tweet the boss instead. So @jeremycorbyn here goes. Members leaving in their thousands over Brexit. Cllrs quitting. MPs will leave. Antisemitism continues in your name. Only you can change all this
— Neil Coyle (@coyleneil) February 13, 2019
In her resignation letter, Cllr Louise, who is a member of the Jewish Labour Movement and Brighton & Hove Progressive Synagogue, writes: "The treatment of Luciana Berger MP has been disgraceful.
"She was faced with a vote of no confidence in her CLP brought by a conspiracy theorist who thinks Israel was behind the 9/11 attacks, and allowed by a CLP Chair associated with David Icke.
"This action was met with a call for her to prove her loyalty to the Party by John McDonnell, and deafening silence by Jeremy Corbyn.
"Luciana Berger is an inspiring role-model, and a real-life contemporary hero. She should be celebrated as a person and MP of outstanding courage and integrity.
"It is unacceptable that Jeremy Corbyn and John McDonell were prepared to throw her to the wolves they have encouraged into the Party."
Read Cllr Louise's resignation letter
Cllr Louise was elected a councillor for the Old Hastings ward in 2018 local elections, after narrowly defeated the Green candidate.
She developed a reputation locally for being one of the most hard-working councillors - but also said become increasingly frustrated by the level of antisemitism in Labour under Mr Corbyn.
Ih her resignation letter, she adds: "The level of denial by Jeremy Corbyn supporters leaves me in despair.
"Decent people hold their hands up in horror when the victims tell them they are being antisemitic.
"People and institutions who are sincere about not being racist learn to change their attitudes, behaviour and procedures for the better. They recognise that they have rightly been called out for unacceptable behaviour."
In a tweet the JLM said: "It is awful that our member, Cllr Dany Louise, of Hastings Council and Brighton & Hove Progressive Shul has felt compelled, like many others, to resign the Labour whip & her Labour membership. When will the party & it's leadership treat this as the urgent moral crisis that it is?"
Last month, it was reported around 60,000 members had left the Labour Party over the past year - with the number likely to rise to 100,000 unless Mr Corbyn altered his Brexit policy and his attitude to antisemitism.
