Sadiq Khan has come from behind to beat former front runner Dame Tessa Jowell to become Labour's Mayor of London hopeful in 2016. The former shadow minister for London won in the fifth round of voting on 58.9% over Jowell's 41.1% share.

The married father of two has been an MP for Tooting since 2005 and is a supporter of Labour leadership favourite Jeremy Corbyn – an early indication that the left-winger is set to be announced as Ed Miliband's successor on 12 September.

"I am deeply humbled to have received the support of tens of thousands of Londoners.I am determined to repay that trust by winning the Mayoral election next May, and making a real difference to Londoners lives," Khan said.

"London gave me and my family huge opportunities. A council house so we could save for a deposit to buy our own home. A secure job for my dad as a bus driver. A great education for me and my siblings, affordable university places and good quality apprenticeships.

"My priorities for Londoners are clear. An affordable and secure home to rent or buy. More jobs with higher wages for the lowest paid. Making it easier to set up and run a successful business. Reducing the cost of commuting and making London's environment safer, healthier and less polluted."

Khan, 44, was behind Jowell in the latest opinion poll conducted before the announcement on 11 September. The YouGov survey, which was commissioned by LBC Radio and questioned more than 450 Labour supporters between 10 and 12 August, put Jowell on 23% and Khan on 16%. But it seems a late surge in support meant the London MP was able to secure 48,152 in the final round of voting over a 33,573 turnout for the former Olympic minister.

Khan was also able to beat Diane Abbott, David Lammy, Gareth Thomas and Christian Wolmar in the contest. He is expected to face Conservative MP Zac Goldsmith in 2016, who will attempt to succeed the bombastic Boris Johnson and hold City Hall for the Tories.

Unite, one of Labour's major donors and one of the biggest trade unions in the UK, welcomed the news. "The selection of Sadiq Khan to be Labour's mayoral candidate is a vindication of the progressive polices he set out during the campaign," said Peter Kavanagh, a regional secretary for the London and south region.

"On housing, transport and employment Sadiq offered a positive vision that will deliver the change Londoners are crying out for and with Sadiq as Labour's candidate I am sure we will win."