Probation officers and court staff have rejected a proposal to affiliate with the Palestine Solidarity Campaign.
Napo - the union and campaign group which represents more than 9,000 officers and family court workers - debated a motion at its annual general meeting in Torquay.
Proposed by the union’s South Yorkshire branch, it claimed “the safety of the peoples of the Middle East is jeopardised by the Israeli occupation of Gaza and the West Bank” and called for an affiliation with the PSC.
Jack Cohen, a Liberal Democrat councillor in Barnet and a former chair of the union's Greater London branch, spoke at the conference and encouraged delegates to reject the proposal.
Following the vote Mr Cohen said: “It is clear that Napo members are against a boycott of Israel and recognise the right of Israel to exist within safe borders. Conference rejected a similar motion last year and voted against affiliation to the PSC by an even greater majority this year.”
At its AGM last year the union rejected a motion proposing to support the boycott, divestment and sanctions campaign against Israel and another seeking to align Napo with the Trades Union Congress’s stance on Israel and the Palestinians.