The prime minister has appointed a special representative to the Middle East, replacing the controversial Lord Levy.
The Foreign Office announced on Friday that UN assistant secretary-general Michael Williams will take up the post.
He will be based in the department and report to both Gordon Brown and foreign secretary David Miliband on progress in the peace process.
However, the appointment is expected to raise questions over whether the role will overlap with that now being performed by Tony Blair.
The former prime minister is now the international envoy to the region of the Quartet, which comprises the US, UN, EU and Russia, having been strongly backed for the position by the White House.
When in Number 10, Blair attracted criticism for choosing his friend and chief Labour Party fundraiser Lord Levy as his own envoy, with the role seen as secretive and unaccountable.
The peer was also seen as being a strong supporter of Israel.
In contrast, Williams comes with strong Palestinian connections.
He is currently serving as UN secretary general Ban Ki-moon's special co-ordinator for the Middle East peace process and his personal representative to the PLO.
His responsibilities will also cover the wider Middle East, including Iraq and Iran.
Williams previously served as a special adviser to foreign secretaries Robin Cook and Jack Straw, during the Iraq war, before moving to New York in July 2005 as director of Asia in the UN's Department of Political Affairs.
Last year, he helped negotiate and implement the Security Council resolution which brought the Israel-Lebanon war to a conclusion.
3 August 2007