Sir Gus O'Donnell has been appointed by Tony Blair to be Cabinet Secretary - the head of the UK's civil service.
Sir Gus is moving from the Treasury
He replaces current incumbent, Sir Andrew Turnbull, in a role which will see him sitting in on Cabinet meetings and paid up to £264,250 a year.
Sir Gus, 52, moves from his current job as permanent secretary at the Treasury.
He previously served as press secretary to former Conservative prime minister John Major, before a stint at the UK embassy in Washington.
He returned to Whitehall when Labour won power in 1997.
Downing Street said he was selected after a competition between several other senior mandarins and the decision was made "purely on the merits of the individual".