Mayor of London Sadiq Khan claimed he will deliver 90,000 new affordable homes in the city after the government handed City Hall £3.15bn ($3.93bn) to spend on lower-cost housing for Londoners grappling with the property crisis.

Housebuilding in London is running at around half the 50,000 new units needed a year to meet demand, driving up house prices and rents in the city, shutting out aspiring homeowners and leaving many people struggling to pay for housing, particularly amid government welfare cuts. Just 13% of all new housing in 2014-15 in London fell into the "affordable" classification.

Labour mayor Khan said the homes will be a mixture of social rent, shared ownership, and the new "London Living Rent", set at a third of average household incomes in each borough. Most of the homes will be delivered by housing associations, which as a condition of receiving grant funding from City Hall will have to hit a minimum of 50% affordable housing in their plans.

"London is in the midst of a housing crisis, with thousands of Londoners priced out of a city they call home," Khan said. "I have been clear that fixing the housing crisis will be a marathon and not a sprint, but I am determined to lead from the front and get on with building genuinely affordable homes for Londoners to rent and buy."

To achieve this, Khan will introduce "Supplementary Planning Guidance" for London, aimed at smoothing the planning process in the city. Currently, developers must negotiate through section 106 agreements with council planning departments the delivery of affordable housing, or funding for other community infrastructure, to secure building permission.

To speed up housing delivery and increase the supply of low-cost homes, Khan will "offer developers a new quicker route through the planning process" if they commit to a minimum of 35% affordable housing in a project.

But Sian Berry, a Green party member of the London Assembly, said Khan is still not doing enough to deliver affordable housing for Londoners.

"These complex proposals fall short of what the mayor promised during the election," Berry said. "He doesn't seem to have got very far towards what most renters in London need to help them now: simple homes for rent that they can afford without conditions attached.

"The London Living Rent homes supported by new funding from the mayor appear to be only for renters who are on track to own their own home already, much like the coalition and Tory governments' multiple failed schemes like 'Help to Buy', 'Rent to Buy' and 'Share to Buy', which have primarily helped people on higher incomes."

During the 2016 London mayoral election, Khan promised that by the end of his term, half of all new housebuilding in London would be affordable.