Emily Thornberry has categorically ruled out the possibility of a Labour government cutting funding for the security of Jewish institutions in Britain, saying that ideas to the contrary were the result of “a major misunderstanding”.

Speaking at the Limmud Festival, the Shadow Foreign Secretary told the audience there was “no way Labour would cut funding”.

In a September interview, Shadow Chancellor John McDonnell had been unclear when asked about whether Labour would maintain funding levels for the security of the Jewish community in Britain.

But Ms Thornberry said: “I’ve spoken to John McDonnell. This is a major misunderstanding. There is no way there will be any cuts to funding for the Community Security Trust (CST).”

Ms Thornberry, the Labour MP for Islington South, appeared at the Limmud event on Thursday in discussion with Jon Lansman, the leader of the far-left Momentum group and a member of the Labour party’s National Executive Committee.

Discussing antisemitism in the Labour Party, Ms Thornberry described how in part it was the result of “lazy undisciplined thinking” by people involved with Palestinian advocacy equating all Jews with events in Israel.

“It’s not Jews. It’s not even Israelis. It’s the Israeli government.”

But she also said there was a “far-left caricature” of capitalism that was “obscene” and revealed antisemitic attitudes, and that with the expansion of the party over the last few years, people who held such views had come in.

“The way things were dealt with last summer was shameful,” she said, in reference to Labour’s seeming inability to deal with the issue of antisemitism.

“It breaks my heart to see how we’ve lost trust with Jewish people… why should people trust us, given what’s happened?”

However, things grew more heated during the question-and-answer session towards the end of the discussion.

“There seems to be an elephant in the room, and that elephant’s name is Jeremy,” said the first audience member to be called on.

The usually sedate Limmud audience vocally registered its displeasure at some of the Shadow Foreign Secretary’s answers, particularly her statement that “I don’t believe there is a racist or antisemitic bone in his [Mr Corbyn’s] body.”

Similarly, her suggestion that Jeremy Corbyn had been unable to deal with the issue of Labour antisemitism properly because he had been so emotionally affected about having been accused of it himself, was met with derision from the crowd.

Jon Lansman told the audience that Labour had “revised our disciplinary process from start to finish.

“The old system wasn’t designed for this,” he said, adding that whereas prior to three years ago the disciplinary unit were having to deal with a few dozen cases a year, there were now hundreds of cases to deal with.

“I sat on [disciplinary review panels of] 100 cases this summer, 80 per cent of which were antisemitism-related.”

On Israel, the Shadow Foreign Secretary said that she had been visiting Israel regularly since the late 1970s, when her father was stationed there with the United Nations, and that “every time I go, the division between the two sides is greater and the chance of lasting peace gets smaller”.

She said that both her position and that of the Labour Party “begins with a strong commitment to the two-state solution… for Israel to be safe and secure, for Palestine to be viable.

“A one-state solution will not give a Jewish democratic state.”

She also described how she thought there was “a hunger for proper leadership” among Israelis and Palestinians, especially from the younger generation.

One audience member asked how, given her comments about “lazy, undisciplined thinking” among Labour members involved in Palestinian advocacy, “how can you serve in a Shadow Cabinet under a Labour leader who would surely fail under your own definition?”

Ms Thornberry responded that “It is my core belief that only the Labour Party can improve this country and make it more socially just.

“And it is for that and many other reasons that I am committed to my party and believe it’s my duty to serve my party and make my leader the best leader he can be, and for us to be part of a leadership team.”