People who fought against Nazi Germany and South African apartheid would “turn in their graves” at the phrases genocide and apartheid being applied to the situation in the Middle East, Andrew Mitchell has said.

The shadow foreign secretary told a Conservative Friends of Israel event at the Tory conference in Birmingham that a “vitriolic outpouring of hostility has crossed all boundaries of sane debate” about the Middle East.

The four Conservative leadership contenders – Robert Jenrick, Tom Tugendhat, James Cleverly and Kemi Badenoch – also spoke at the late-night event, setting out their support for Israel.

In Parliament, on the streets of London, in university campuses around the world, we have witnessed a form of hysteria

Risk of heightened conflict in the Middle East continues to loom after Israeli air strikes killed the leader of Lebanese militant group Hezbollah over the weekend.

Speaking at the Tory fringe event, Mr Mitchell likened the situation to the phrase that the night is always darkest before dawn, and insisted there was hope for peace.

But the shadow foreign secretary had harsh words for the most vocal critics of Israel, telling the audience: “In Parliament, on the streets of London, in university campuses around the world, we have witnessed a form of hysteria. Words like apartheid, genocide.

“Words that would make those who fought against Hitler and against the apartheid in South Africa turn in their graves. The vitriolic outpouring of hostility has crossed all boundaries of sane debate.

“Some of it may be well intentioned, people must be free to express their anger and protest the government of Israel and the genuine humanitarian concerns for the suffering we are witnessing.”

Ms Badenoch claimed a group of independent MPs who stood on pro-Gaza tickets had been “elected on the back of sectarianism”.

The group, who mainly won seats from Labour MPs, have announced they will sit together in Parliament alongside former Labour leader Jeremy Corbyn.

Ms Badenoch described them as a “new threat”, telling the Conservative conference fringe event: “We must not pretend that these people are a minority.

“We have to fight this ideology that has no business in our country.”

Mr Jenrick said he would move Britain’s embassy in Israel to Jerusalem if he were in power.

He added: “I stood in this very hall a few years ago and I said it then, as I say it now tonight, and if the Foreign Office or the civil servants don’t want to do it, I will build it myself.

“So friends, the next Conservative Party manifesto will say build the embassy in Jerusalem, recognise Jerusalem as the legitimate capital of the state of Israel.”

Mr Cleverly, the former foreign secretary, said Israel has his “personal support” in the “defence of your democracy”.

“No friendship is completely unqualified but when a friend has experienced something as brutal as the atrocities of 7 October you stand shoulder to shoulder with them,” he added.

Mr Tugendhat said the Conservatives should be “absolutely clear that we will always stand with democracies defending themselves” and hit out against Labour’s partial arms embargo on Israel.

“To those who say there should be an arms embargo on a country defending itself against terror, I say no,” he added.