Green belt homes ‘needed’ to solve housing crisis, Sadiq Khan says
London is suffering a chronic housing shortage. Lacklustre rates of housebuilding have helped push up the cost of a home to well beyond the reach of ordinary Londoners.
The price of an average terrace house in Camden has roughly tripled compared to twenty years ago to more than £1.5m today, Land Registry data shows, while a semi-detached home in Richmond has just about quadrupled to £2m. It’s a similar story across many parts of the capital.
To make matters worse, rates of affordable housebuilding have collapsed compared to where they were just a few years ago.
In the year to March 2025, just 3,661 affordable homes were started under the mayor’s affordable housing programme, according to data released this week. That is the second lowest total since records began in 2008/9, eclipsed only by last year’s figure of 2,358 and is well below target.
For London mayor Sadiq Khan, the explanation is simple: we’re running out of space.
“We simply aren’t going to have – even if we build on every single piece of brownfield site – a supply of homes to meet the demand. That is the reality,” Khan tells City AM.
London needs around 90,000 extra homes to be built each year to keep pace with demand. To achieve this – or anything close to it – the mayor has embarked on a major strategic pivot. For the first time, Khan is proposing building homes on the green belt, a vast expanse of protected land bordering the capital, a move he describes as “the biggest change in housing policy for a number of decades.”
“When I was growing up I assumed the green belt was green and pleasant land, rich in wildlife [but much of it is] poor quality, badly maintained, inaccessible to Londoners,” he says.
“I’m not suggesting that we build on our gorgeous parks, I’m not suggesting that we’re building on our lush green spaces in London. What I am saying is we should now be actively exploring homes we can build there – with conditions.”
Urban sprawl
The green belt was formed in the mid-20th century after a boom in house building sparked fears of urban sprawl. It now encompasses an area multiple times the size of London. That has made the capital’s borders stay largely unchanged over the past 70 years when comparable capital cities have grown, putting pressure on its ageing housing stock.
Despite its name, the green belt is not designed to preserve any specific areas of natural beauty or valuable heritage. In fact, less than a quarter of it is made up of protected conservation areas.
“The green belt was a completely undiscriminating piece of legislation – it didn’t take any account of land quality – it was purely a mechanism of urban containment,” Robert Colvile, director of the Centre for Policy Studies and an advocate for green belt construction, said.
“There is plenty of room to expand London sensitively into the green belt without targeting precious conservation areas.”
Areas ripe for development include 12 per cent of the green belt designated “low grade” agricultural land, of little value for farming, on which millions of homes could be built.
That is likely to form a key component of the mayor’s new plan to allow pockets of the green belt to be “released” for development over time, subject to conditions such as the availability of local transport.
‘Switch in tack’
But why the sudden change of heart? Khan is now entering his tenth year in office – longer than any of his predecessors and more than enough time to have already drawn up a comprehensive housebuilding strategy.
“The change of government last July means we’ve got a government that wants to work with me to address the housing crisis which I think is the biggest issue facing our city,” Khan says.
Colvile said that explanation was disingenuous.
“He’s now suddenly talking about these issues but his record is awful on housebuilding,” Colvile said.
“People have been talking about this for years and the mayor has barely said anything about this before…on industrial land the [Mayor’s team] have pushed back against people like us who argue that there was plenty of scope to release land.
“More joy in heaven over one sinner who repents – but this is certainly a switch in tack from the mayor and his administration.”
Green belt house building is likely to attract a mountain of opposition from those living in and around it. The mayor told City AM he won’t extend his controversial ULEZ car charge scheme to any part of the green belt built on, in signs of a possible olive branch to locals readying their pitchforks.
Following a consultation, Khan’s ideas for the green belt will be fleshed out in a new London Plan strategy document, due to be published next year, in what the mayor hopes will be a call to action for developers.
But by then, we will be at least halfway into Khan’s third, and likely last, term in office. Few judge the mayor’s house building record as a roaring success – and time is running out to rescue it.