Representatives of all the main political parties except Ukip voiced their opposition to a boycott of Israel and a ban on shechita at a Board of Deputies hustings.
Conservative cabinet minister Sajid Javid joined figures from Labour, the Liberal Democrats and the Green Party in telling the audience of 100 deputies that the government must maintain the rights of the Jewish community.
The representatives, who were speaking ahead of May's general election, answered questions from deputies on subjects ranging from faith schools and hate speech at universities to Israel's security.
Culture secretary Mr Javid ruled out any ban on shechita, saying that he would not stomach any proposal which adversely affected smaller communities.
"A civilised society is judged by how it treats its minorities," he said. "I have no time for any ban on it. It would not happen under the Conservatives."
I have no room for cultural boycotts at all - Sajid Javid
Last month Ukip's national executive committee voted to support the banning of non-stun slaughter. The party did not send a speaker to the meeting.
Mr Javid also condemned the Boycotts, Divestments and Sanctions (BDS) movement for perpetuating what he called "a form of the oldest hatred in the world". He said: "I have no room for cultural boycotts at all. "
Labour MP Stephen Twigg, a former education minister, agreed, referring to the Board's Jewish Manifesto, which outlines 10 values it asks all politicians to support at the election.
"The first point is around respect for the Jewish community's traditions, and I think that is absolutely of vital importance. There is no question of the Labour party supporting a ban on shechita," he said.
He said that attempts to delegitimise Israel were "completely unacceptable. The Labour party is clear that we do not support boycotts".
Green Party equalities spokesperson Benali Hamdache said that there was a need to support kosher and halal slaughter against claims that they involved cruelty to animals. "We need to challenge the horrible misconceptions which are out there. Kosher and halal meat have a long legacy valuing humane killing of animals."
He also spoke out against BDS's actions, though he fell short of condemning the boycotting of Israeli corporations, a policy he supported at last year's National Union of Students conference.
He said the focus on boycotting Israel was "problematic. There are many states around the world slaughtering gay people and committing atrocities. We need to look at human rights as a whole".
The Lib Dem deputy leader of the House of Commons, Tom Brake, said he was "very proud" his party had allowed religious slaughter to continue while it was part of the coalition government, adding that the Lid Dems do not support a boycott of Israel.
