Susan Hall, who was selected to run for the mayoralty in July, made the comments at the Conservative Friends of Israel event on the fringes of the Tory party conference in Manchester.

She told the audience that one of the "most important" things she would do for Londoners would be to make the city "safer" - particularly "for our Jewish communities".

But the Board of Deputies of British Jews said Mr Khan had "treated our community with friendship and respect".

The organisation said it hoped to hold a hustings with all the candidates before the mayoral vote next May "where it will be clear that while London Jews may have varying political views, there is no fear present at all".

Read more: 'Rishi reset' derailed by HS2 - Tory conference latest

Speaking on Monday, Ms Hall asked for "as much help as [she] can get in London" because Mr Khan "needed to be defeated".

"I know how frightened some of the community is because of the divisive attitude of Sadiq Khan," she said.

"One of the most important things that I will do when I become mayor of London is to make it safer for everyone, but particularly for our Jewish community.

"I will ask for as much help as I can get in London, because we need to defeat him."

Her comments immediately drew criticism from politicians and Jewish groups.

Labour's shadow health secretary, Wes Streeting, said her remarks were "divisive and disgusting".

"Sadiq Khan has repeatedly stood by London's Jewish communities in the fight against antisemitism," he wrote on X, formerly known as Twitter.

"Susan Hall's dog whistle politics have no place in London. Will decent Conservatives ever call this out?"

Read more:
Has HS2 reached its terminal? - Paul Kelso analysis
Three main points from Hunt's speech - Ed Conway analysis

Mike Katz, the chair of Jewish Labour, said Ms Hall was "vile, ignorant and wrong" and urged her to apologise.

"Sadiq has consistently gone out of his way to work with the Jewish community. He stood with Jewish Labour when we spoke out on antisemitism in Labour," he said.

"For Susan Hall to try to use this as a dog whistle is beneath contempt. She should apologise.

The Jewish Labour Movement accused Ms Hall of "gutter divisive politics that seeks to use the Jewish community as political pawns".

"We had quite enough of this from Jeremy Corbyn and saw him off - and have no patience for it from Susan Hall," it said.

Sky News has approached Ms Hall for her response. The Conservative Party has declined to comment.