A package of emergency measures has been unveiled to boost house building in London after more than a third of boroughs recorded zero new home construction starts in the first quarter of this year.

The moves will unlock development by making sites more viable and incentivise developers to get spades in the ground through a fast-tracked planning process for sites with at least 20% affordable housing.

Design guidance will be removed that constrains density alongside temporary relief from development levies for schemes able to start promptly and guarantee affordable homes for Londoners.

The Mayor will be handed new powers to fast-track housing including the ability to review and call-in schemes of 50 homes or more where boroughs are minded to refuse.

City Hall can also become the decision-maker regarding developments of 1,000sqm or more on green belt.

The Government is also confirming an initial £322m to establish a City Hall Developer Investment Fund to ensure the Mayor can further increase housebuilding.

The measures follow on from action taken by the Building Safety Regulator to speed up decision-making relating to building control applications for high-rise buildings.

Housing Secretary Steve Reed said: “I have worked closely with the Mayor of London to give the capital the shot-in-the-arm it needs to ensure more Londoners have an affordable home of their own.”

The Mayor of London, Sadiq Khan, said: “There’s now a perfect storm facing housebuilding in London due to a combination of high interest rates, the rising cost of construction materials, the impact of the pandemic and ongoing consequences of Brexit. All of this means we are now in the midst of the most difficult period for housebuilding since the global financial crash.

“With these significant new powers and the initial £322 million of funding from the government – plus the short-term emergency action to get more investment flowing into affordable housing – I’m confident that we can kickstart housebuilding and deliver more of the affordable homes Londoners badly need.”