Sadiq Khan could build many more houses in London if he was “brave enough”, a former Tory MP running for Mayor of London has said.

Rory Stewart said the threat of compulsory purchase could spur on development of disused sites in the capital.

The current Mayor wants to build 65,000 homes a year, to meet London’s housing needs as the population grows.

He is currently drafting a new London Plan – the planning document that will set the framework for building for at least a decade.

But the Mayor has been told he must lower his target to 52,000 homes a year, because his current plans set unreasonably high goals for building on small sites.

The Government’s independent planning inspectors also said he should consider building on the Green Belt.

But Mr Stewart believes the inspectors’ report was “pessimistic” and there could be more development within the city.

He said: “The Mayor of London has enormous power – he just doesn’t choose to exercise it.

“He has more power than the Mayor of New York but you wouldn’t have thought so.”

Mr Stewart said developing Transport for London (TfL) land, setting up mayoral corporations for major housing projects, partnering with the private sector or borrowing money to buy land could all help to build more homes.

He said: “If they [City Hall] wanted to, they could do compulsory purchase – that’s got huge powers to transform housing.

“There are sites in London which are basically disused brownfield sites lying empty.

“It may be that you do have to at least have the threat of compulsory purchase to bring that land back onto the market.

“Otherwise people just sit there forever hoping the land value is going to go up.”

He added: “If you take a helicopter down the estuary from Greenwich onwards there’s just space after space where you could put houses – where the Mayor of London could do that, if the Mayor was brave enough.”

Almost 41,000 new homes were built in London last year, according to research by estate agent Savills.

The figure is almost 2,500 more than in 2015, the year before Mr Khan took office – but London house-building has grown slower than any other region.

London Labour have not responded to a request for comment.