Prime Minister Gordon Brown has reiterated Britain's commitment to the diplomatic campaign against Iran's nuclear programme.
Speaking at the annual reception of Labour Friends of Israel on Monday at Labour's conference in Manchester, Mr Brown said that Iran had only two alternatives - to comply with the demands of the international community or steadily to isolate itself.
The packed reception at the Midland Hotel was the only event on the conference's fringe circuit attended by both Mr Brown and the man widely seen as his main leadership rival, Foreign Secretary David Miliband.
Mr Brown spoke of his own close family and personal ties to Israel, and called Prime Minister Ehud Olmert, who resigned this week, "a personal friend".
He had, he said, been very pleased that he had been the first British PM to address the Knesset when he visited Israel earlier this year.
Mr Miliband elaborated on the speech he had given earlier in the conference in which he had spoken of the need for a secure Israel next to a viable Palestinian state. The Foreign Secretary told LFI supporters that he had thought at length about that particular part of his speech. All supporters of Israel, he said, had to realise that there was a closing window of opportunity to reach a two-state solution.
The reception was also attended by Israeli ambassador Ron Prosor and MK Colette Avital. The representative of the Israeli Labour Party, she thanked Mr Brown for his speech to the Knesset.
Long-time LFI leader Mike Gapes, chairman of the Commons Foreign Affairs Select Committee, said later: "The fact that both Brown and Miliband attended the event is very significant, and shows this government's support for Israel's future."
At the conference itself, in a session devoted to crime, the Jewish Labour Movement's Mike Katz highlighted a recent rise in antisemitic incidents and called on the party to do more to counter the campaigning by the British National Party, which polled more votes than Labour did at the Henley by-election.
The Holocaust Educational Trust also held a well-attended fringe meeting at the party conference.