Ms Ryan was warmly received at the JW3 centre in London when she chaired a discussion on Israel between Jewish Agency chairman Isaac Herzog and former Jewish Leadership Council chairman Sir Mick Davis.
While Labour leaders pointed out that antisemitism complaints involved only 0.1 per cent of their membership, she said: “If it is such a tiny problem, then why has it taken three and a half years to find any way to resolve it?”
Although she believed the numbers were a little bigger, she said: “It is not a matter of numbers. Institutional racism is within your very organisational structures, within your processes and within your ideology. That’s the problem.”
She said although sad, leaving the party after 38 years had been “perhaps the easiest decision I have ever made.”
Last autumn, she had made a commitment to stand by the Jewish community whatever the personal cost.
Referring to MP Luciana Berger who also quit the party, she said: “I could not see a young Jewish woman driven out of the party by antisemitic abuse and nobody from the leadership reaching out to her.”