Sadiq Khan is set to campaign for rent controls in London as part of his 2020 reelection strategy.
Any new laws that would forbid landlords from raising rents over a certain amount would have to be sanctioned by government.
Speaking to the Guardian, Mr Khan said: “London is in the middle of a desperate housing crisis that has been generations in the making.
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“I am doing everything in my power to tackle it, including building record numbers of new social homes, but I have long been frustrated by my lack of powers to help private renters.”
In 2016, the English Housing Survey conducted research that predicted the number of people renting in London could rise to 60% of the city’s population by 2025.
YouGov research for City Hall found that two thirds of the 2.4 million people renting in London would support rent controls.
'Landlords could sell up'
Some organisations have said that rent controls may not have the intended consequence of making homes for affordable.
Housing charity Shelter warned last year that such a policy “would force a significant number of landlords to sell their home, as they could make more money that way”.
“That might be good for middle earners – a glut of homes suddenly for sale might become available.
“But this is where the risk comes in for low earners. They can’t afford to buy, and increasingly rely on the private rented sector.
“As landlords sell up, they would be left with fewer places to live. In the absence of a much larger supply of council and social housing, that risks pushing people into homelessness.”
Tenant groups like Generation Rent have been advocating for rent controls for some time - in 2014 they put forward a proposal, backed by Labour MP Diane Abbott, calling for rents to be calculated at half the value of a property’s council tax band.
Campaigner Duncan Stott, a former director of the affordable housing campaign group Priced Out, welcomed the news of Sadiq Khan’s plans on Twitter, and shared a link to Generation Rent’s 2014 proposal.