Tony Blair has faced further questions about his leadership on a trip to Israel for talks on Middle East peace.
In a joint press conference with his Israeli counterpart Mr Blair repeated a call that he wanted an end to personal attacks in his party.
Earlier in a speech in London he warned the Labour Party risked defeat at the next election if in-fighting continued.
His comments came after former Home Secretary Charles Clarke criticised the PM's likely successor Gordon Brown.
At the press conference in Jerusalem Israeli premier Ehud Olmert said: "Prime Minister Tony Blair is a true and profound friend of the state of Israel and a dedicated friend of the Middle East. Britain is Israel's staunch partner."
He said Mr Blair had worked actively to "promote progress on all tracks, to promote stability in the Middle East."
Mr Blair was asked whether he regretted his support of President George W Bush now that he had announced his plans to leave office.
"I don't think it has ever been a mistake to stand shoulder to shoulder with America in the aftermath of 9/11," he said.
He continued: "One of the most changed aspects of leading a country such as Britain today is that the stability of this region also affects the stability of my country.
"We live in a world in which how you fare here, how Israel does, issues to do with the Lebanon, and Israel and Palestine, are issues that also concern how my country fares."
Mr Blair faced further questions about his leadership although he said that they would be "disrespectful".
Asked whether he would publicly endorse Gordon Brown as his successor, Mr Blair said that his previous comments contained "everything any sensible person could ask on that issue.
Earlier in the day Mr Blair made a keynote speech at the 10th anniversary conference of a New Labour think tank, the Progress Organisation, in central London.
He said: "We can either - after the kind of spasm of last week retreat into personal attacks... or we can say we are going in a mature, intelligent, and capable way to describe to the country what we've done."
Elsewhere Mr Clarke accused Mr Brown of being a "control freak", lacking the courage to take tough decisions.
He told the Daily Telegraph that Mr Brown was "deluded" about his relationship with the prime minister.
But Northern Ireland Secretary Peter Hain described Mr Clarke's comments as "quite extraordinary" and said Mr Brown would be an "excellent successor".