Former MP Oona King has backed Ken Livingstone to regain the London mayoralty after he beat her for the Labour candidacy to take on Boris Johnson.

Mr Livingstone, whose two previous terms as mayor saw him open a rift with the Jewish community, will take on the current Tory incumbent in 2012.

Ms King polled 31 per cent of the vote on her return to the political spotlight. She lost her Bethnal Green and Bow parliamentary seat to George Galloway following an acrimonious campaign in 2005.

Following her defeat to Mr Livingstone, announced on Friday, Ms King said: “Now we must turn our attention to the real fight; the wasted mayoralty and lack of vision of Boris Johnson. Ken Livingstone is a formidable politician who has never given up the fight. I am sure he will battle for London as he always has and we must give him our support as he does so.

“So, we are united again as Team Labour. All of us must do our best to make sure Ken Livingstone is the next Mayor of London. And no one wants to see Ken defeat Boris Johnson more than I do.”

Mr Livingstone’s controversial previous stint running London included him welcoming radical Islamic cleric Yusuf al-Qaradawi and comparing a Jewish journalist to a concentration camp guard.