By politics.co.uk staff

Former Labour MP Oona King will take on Ken Livingstone as the pair struggle for the party’s nomination for the 2012 London mayoral election.

Mr Livingstone served as London mayor from 2001 until 2008, when he was defeated by Conservative candidate Boris Johnson.

He wants to stand again but Ms King could present a major threat.

“I have announced today my decision to stand to be the next mayor of London,” she said in a statement on her website.

“You will see more details about my campaign for London’s future. in the coming days and when I officially launch my candidacy on Wednesday this week.”

Ms King was elected MP for Bethnal Green and Bow in 1997 but was ousted by Respect firebrand George Galloway in 2005.

She has focused on community issues since leaving parliament, chairing the Institute for Community Cohesion and the Rich Mix Cultural Foundation.