Former Israeli Defence Minister Amir Peretz made a visit to the UK last week in defiance of attempts to serve him with an arrest warrant for war crimes. Mr Peretz held the defence portfolio during the 2006 Lebanon war.
Earlier this year he announced his bid to regain the Labour Party leadership, having led the party from 2005 to 2007.
Mr Peretz was notified last week by the Israeli Foreign Ministry that there would be an attempt to serve an arrest warrant on him in London.
The JC understands that he was urged to cancel his visit but refused. The Israeli embassy prepared a standby legal team.
Plans had been made for him to speak at an invitation-only meeting last Friday, hosted by the Next Century Foundation, a conflict resolution organisation. It is believed that activists planned to ambush him there.
William Morris, secretary-general of the NCF, told the JC that he had received a last-minute message that Mr Peretz would not be attending, but received no explanation.
According to diplomatic sources, after the cancellation of the event activists initially believed Mr Peretz was not arriving in London, but they learned later of his presence in the UK and resumed their efforts. At this stage, he agreed to bring his departure forward from Sunday to Saturday night.
According to the Jerusalem Post, retired Major General Danny Rothschild, who chairs the annual Herzliya security conference, was also forced to cut short a recent trip following reports that an attempt was being made to arrest him.
Army Radio reported that this was launched in response to the arrest last week in Britain of Raed Salah, leader of the northern Islamic Movement.