Jeremy Corbyn has pledged to campaign with Labour's London Mayoral candidate to rid the capital of the government's "social cleansing".
During his acceptance speech at the QEII Centre, Mr Corbyn said he will be fighting alongside his "friend" Sadiq Khan and that London needed a London Mayor.
Mr Khan was selected as the party's candidate on Friday after beating front-runner Tessa Jowell in the fifth round of voting and like his new leader, identified housing as a major platform on which he would campaign in next year's election.
To huge cheers in the hall, Mr Corbyn was scathing of the government's social policies in the capital.
"I am fed up with the social cleansing of London by this Tory government and its policies," Mr Corbyn said.
"We need a Labour mayor in London who can ensure we do house everyone in London, we do end the sky high rents, we do end the insecurity of those living in the private rented sector.
"We need a Labour mayor to bring that about in this wonderful great city and Sadiq is the man to do it."
Earlier, Mr Khan told the special conference he still "couldn't quite believe" he had been elected as Labour's candidate.
"I am deeply humbled by the faith you have shown me." he said, before admitting that winning back City Hall next May will be "a huge challenge".
"This isn't just about London," the Tooting MP said. "Winning next year will give us a chance to show the difference we can make to people's lives when we win power."