Nigel Farage has been fiercely criticised for saying Jews living in the US hold disproportionate political power.
The former Ukip leader, who has close ties with President Donald Trump, appeared to agree with the claim American Jews hold financial control over the political sphere.
Mr Farage made the remarks during a discussion on LBC radio station about whether Russian influence had really helped Mr Trump be elected.
After a caller who referred to himself as “Ahmed” told Mr Farage he thought the pro-Israeli lobby in the US was equally dangerous to alleged Russian hacking, he appeared to concur with the listener.
The politician said: “Well the Israeli lobby, you know, that’s a reasonable point, Ahmed, because there are about six million Jewish people living in America, so as a percentage it’s quite small, but in terms of influence it’s quite big.”
After Ahmed claimed Israel has both the Republican and Democrat party “in their pockets”, Mr Farage said: “In terms of money and influence they are a very powerful lobby”.
The Brexit campaigner then thanked “Ahmed from Leyton” whom he said “makes the point that there are other very powerful lobbies in America, with the Jewish lobby, that has links with the Israeli government, is one of those strong voices”.
Joe Glasman, Head of Political and Government Investigations at Campaign Against Antisemitism, has called for Mr Farage to apologise for his “deplorable” remarks.
“It is common for countries to lobby their allies, and Israel is no different, but in his call with Ahmed, it was not merely alleged that Israel conducts lobbying, but that it is carried out by the entire Jewish population of the United States and that in doing so American politics are subverted,” he told The Independent in a statement.
“Counting all American Jews as lobbyists with disproportionate power and both major political parties in their financial grips is the stuff of antisemitic conspiracy theories.”
“Mr Farage should immediately withdraw his deplorable comments and apologise for them, or LBC should relieve him of his duties. We await Mr Farage’s urgent apology and in the meantime, we will be asking Ofcom to open an investigation.”
A spokesperson from the Board of Deputies, an organisation which describes itself as a “democratic, cross-communal voice”, said: “Nigel Farage’s clumsy use of the terms Israel and Jewish lobby interchangeably and his reference to their ‘power’ has crossed the line into well-known antisemitic tropes.”
The remarks prompted anger on Twitter where critics argued the politician had perpetuated anti-semitic stereotypes of Jewish wealth.
Adam Langleben, a Jewish Labour councillor, said the politician had gone “full conspiracy”.
He said: “Person calls in and compares AIPAC to Russian collusion. Farage plays up influence. Interchanges “Israeli” and “Jewish” Lobby.”
“Worst part of the Farage ‘Jewish lobby’ monologue, was his 6m Jews remark. As if only Jews support Israel. Way off,” said journalist, Jack Mendel.
“Nigel Farage spewing anti-Semitic conspiracies over the radio, nobody cares because he’s right-wing”, said one.
“Nigel Farage slips into antisemitic tropes of Jewish power and wealth. Shocked, I tell you, shocked!” added another sarcastic critic.
Mr Farage has fostered an alliance with President Trump and appeared alongside the billionaire property developer on the campaign trail and attended presidential debates to express support for him. Mr Farage was also the first foreign politician to meet Mr Trump in person and attended a “heroes and villains” costume party with him in New York last December.