The former managing director of JWT and chief executive of Ofcom has been given a peerage as part of the prime minister's reshuffle.
The appointment of Carter in January sparked in-fighting between Brown's old guard and newcomers such as Carter and former JWT executive David Muir, who Carter recruited to the role of director of political strategy.
Carter, whose first job was as a graduate trainee at JWT working on the Kellogg account, became one of Brown's highest paid advisors when he took the £140,000-a year role at No. 10. But before he made the move into politics he was paid about £500,000-a-year at public relations firm Brunswick where he held the position of chief executive.
Over the past few months he is said to have become increasingly frustrated with life at Downing Street and was reportedly sidelined at the beginning of September in what was then seen as a victory for the ‘old guard'.
Controversially, Peter Mandleson has also been brought back into the cabinet as secretary of state for business, replacing John Hutton.