The first deals struck under the initiative include a plan for 525 new homes in Waltham Forest, and 1,000 new homes in both Newham and Lewisham over the next four years.
As part of Building Council Homes for Londoners, Sadiq has criticised the government for failing to give councils the freedoms they need to ensure all those homes sold under Right to Buy rules are replaced. "Council homes for social rent bind our city together, and they have been built thanks to the ambition of London's councils over many decades. I share the Mayor of London's commitment to kick-start major council housebuilding in the capital as the only way we can realistically tackle the housing crisis".
Many council houses were built in the 1970s but since then, the rate of building has slowed down.
This marks the first ever City Hall programme dedicated to supporting social housing.
Khan accused the government of having "turned its back" on local authorities and "hampering" their ability to build new homes.
I am offering councils expertise and resources from City Hall to scale up their homebuilding programmes, and I will help them to replace homes sold through Right to Buy.
Mt Khan has called the government up on their failure to replace social housing lost under Right to Buy and hopes London councils will be granted with higher powers to replace as many homes as possible.