Mr Clement, who has resigned with immediate affect as Bexley's leader, will be responsible for boosting links between the London boroughs and City Hall.
The former London Councils executive member for crime and public protection said: “Bexley has been my life for the past 10 years. The decision to leave was a very difficult one, but I believe you can only do one job really well.”
O'Neill acting leader
Bexley deputy leader Teresa O’Neill (Con), has taken over as acting leader until the council's annual meeting on 14 May 2008.