Sadiq Khan has slammed former mayor Boris Johnson's flagship housing scheme for failing to stop new London homes being sold as "golden bricks" to overseas investors.
Johnson's Concordat scheme, which was launched in 2014, was pitched as the solution to stopping major developers advertising London homes abroad first for overseas buyers, who had months more notice than Londoners to purchase them.
More than 50 developers signed up to the scheme, including Cadogan, Taylor Wimpey and British Land.
However, Khan today criticised Johnson for designing a "toothless" Concordat that meant homes could still be launched overseas at the same time they were made available in London. He also slammed the scheme for having no official Greater London Authority process of monitoring whether the signatories to the Concordat were keeping to their promises.
Labour has previously derided London housing costs as the "biggest single blight" on the capital.
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Without powers or processes to enforce the marketing activities of the signatories, Khan claimed evidence suggested that when it was broken there was no effective sanction available to the mayor.
"We all know that Boris Johnson left the cupboard bare on housing in London, and it will be a hard and long process to fix his mess," Khan said during Mayor's Question Time, as part of an ongoing audit of the London housing crisis.
"The previous mayor's 'Concordat' is yet another housing failure we have inherited – a scheme that claimed to help Londoners get first dibs on new properties but in reality did nothing to stop the problem of London homes being sold off-plan as gold bricks to overseas investors.
"This is the same Mayor who oversaw planning permissions being given with just 13 per cent affordable housing last year.
"I am determined to give more Londoners 'first dibs' on more new and affordable housing, and have asked officers to bring forward a range of meaningful options to replace Boris Johnson’s failed, frankly embarrassing attempt," Khan added.
A spokesman for Boris Johnson said in response to Khan's comments: "100,000 affordable homes, a record, and a manifesto promise delivered. 18,000 affordable homes in 2014/15, a 30-year high.
"Every jot of city hall owned land released for development. Contrast that with the broken promises and empty pledges of Sadiq Khan. He's only been in office six weeks and already he's foundering: 80,000 homes a year – scrapped, 50,000 – scrapped, a fares freeze – scrapped. He should get on with doing rather than dodging."
Liberal Democrat London Assembly member Caroline Pidgeon supported Khan's takedown of the scheme.
"Sadiq Khan is absolutely right to criticise the weak measures adopted by the previous Mayor," Pidgeon said. "However, criticising the last Mayor will not in itself deliver one more home for Londoners. Sadiq Khan must now set out how he will not repeat the mistakes made by the last Mayor."
In contrast, Conservative London Assembly member Andrew Boff hit back at Khan's criticism of the Concordat.
"Contrary to popular belief, just three per cent of London homes are foreign-owned," Boff said. "The mayor is simply using this contentious issue as a stick to beat his predecessor and distract from his own lack of housing targets and manifesto u-turns.
"The reality is there was only ever one example of a developer breaking Boris' Concordat. It is time Sadiq started focusing on what he plans to do to solve London's housing crisis rather than looking over his shoulder at what the previous mayor achieved."
Galliard was the only group found to have broken the Concordat, which was uncovered when a national paper alerted the previous administration that the property developer was targeting Hong Kong customers before Londoners.
Meanwhile, in another move on housing, Khan today refused permission for the development of a three-storey football stadium and two four-storey blocks of flats in Chislehurst, Bromley, that would have been built on Green Belt land.
"I am determined to oppose building on the Green Belt, which is now even more important than when it was created," Khan said.
"Working with my planning team, I will continue to use my full range of planning powers to further strengthen protections for open and green spaces in the London Plan and ensure we are making the most of brownfield sites across the city, including the vast swathes of public land which are ripe for building homes for Londoners."