Southwark has won the London Local Authority of the Year 2002 award for its "continuing commitment to improving the environment in the Borough".
The RIBA/CABE award was presented at the Royal Festival Hall in recognition of a series of high-profile new developments within Southwark including Tate Modern and the GLA headquarters and also for smaller initiatives which contribute to a better quality of life for those who live and work in the Borough.
Southwark Council Leader Nick Stanton said: "We see it as recognition of the leading role taken by our architects and planners in helping make Southwark a pleasant place to live, work and visit. This award reflects our commitment to improving the environment and shows us to be at the cutting edge of local authority design and planning."
Schemes which impressed the judges include the Jubilee Line extension and the Millennium Bridge.
Judges also mentioned the Iroko community housing development in Coin Street and the Southwark Cathedral Millennium Project.
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