I'm thinking of starting a support group. Our community is full of charities and counselling services covering every cough, spit and ailment in the medical dictionary. But I think we need another.

I'd call it "I used to vote Labour, but now I don't know what to do." To those six Labour supporters who wrote a letter to Ed Miliband last week, expressing their concerns about Ken Livingstone's obsession with Israel, to the brave Jonathan Freedland, I say: "Comrades! You are not alone!" Together, I daresay we could add hundreds of signatures to that letter. Figures seem to suggest one in three Labour voters won't back Ken.

I imagine we'd sit in a semi-circle, heads in our hands, recalling how Ken campaigned for Lutfur Rahman - an independent with alleged links to the Islamic Forum of Europe - to be mayor of Tower Hamlets, rather than the Labour candidate. We'd grimace at the memory of his chumminess with controversial Islamic cleric Yusuf al-Qaradawi.

In our chilly community centre hall, sat on plastic folding chairs, we'd wear badges identifying our constituencies. Mine would probably draw some extra sympathy. I live in Islington North, the constituency of Jeremy Corbyn, the Press TV commentator who would have chaired the meeting with Palestinian leader Raed Salah at the House of Commons - had the Home Secretary not attempted to have Saleh banned from the UK.

This week I plan to return my membership card and cancel my direct debit. I joined because I wanted Labour to stay in government in 2010. I consider myself centre-left, and believe in strong social welfare policies and protecting the NHS from privatisation.

As a member, I am repeatedly asked to campaign with my MP and for Ken. And although his campaign newsletters are now going directly into my junk mail, despite everything, I had some vague notion of being able to grit my teeth and vote Labour in May.

Ken's remarks last week were not the final straw. The rub is the reaction of the party I felt a loyalty to. The letter came from loyal Labour campaigners and councillors, who were worried about the man their party had picked to represent them.

Can it really be true that nobody in the campaign HQ finds it troubling that Ken believes that all Jews vote Conservative, and that "Jew", "Israeli" and "Zionist" can be used interchangeably?

This is not an attempt to smear Ken or the party in order to rally support for his opponent. But my concerns have been dismissed as irrelevant, or as "electioneering" against him. It is one small mercy that nobody has dared use the word "conspiracy" yet.

I have written three times to Ed Miliband and other party leaders in a personal capacity. In July, I expressed my concern about my MP's jaunt to Beirut, for Viva Palestina's Summer University, alongside Palestinian hijacker Leila Khaled, and Azzam Tamimi, who has spoken of his desire to become a suicide bomber. No response.

I emailed expressing my alarm at Ken's backing for Rahman. No response. And having been invited to a fundraising night for Ken at the "Shadow Lounge", I wrote that he should spend less time there and more time working out how large his cheque to HMRC should be. No response.

The account given by the Jewish Labour supporters suggests that what Ken is doing is brushing off the concerns of even of his most loyal supporters, and attempting to define us not only as rich Tories, but as just a "religion", not a culture, ethnicity or a people.

This mayoral election will be the first election I do not vote Labour. If Corbyn stands in the next election in Islington North, I will not vote Labour then either. It is sad that it is the people, and not the policies, which have driven so many Jewish voters away.