Val Shawcross, who has been a member of the London Assembly for the past nine years, has been selected as the Labour Party's parliamentary candidate for the Bermondsey and Old Southwark constituency.
She stood down as prospective parliamentary candidate in order to concentrate on her work for Gordon Brown. She was widely credited as the author of Gordon Brown's well-received speech at last year's Labour Party conference.
In the selection vote Val Shawcross beat left-wingers Cllr Gordon Nardell (The Lane ward, Peckham) and former miner Christopher Herriot.
Speaking after the selection meeting, Ms Shawcross said: "This is a fantastic area to represent. It's steeped in history and got some really wonderful people. I can't imagine a constituency that I would be happier to work for.
"I think that the time has come when this constituency did have a new representative.
"There are a lot of issues here with the poor performance of the council and I think this area is in the front line of regeneration. It does need a strong voice to stand up for it."
Val Shawcross is a former leader of Croydon Council. Since 2000 she has been the London Assembly member for the boroughs of Lambeth and Southwark.
The parliamentary constituency is currently known as North Southwark and Bermondsey. It will be renamed Bermondsey and Old Southwark at the next general election.
Confirmed candidates so far include: