When three London councils launched a judicial review against Sadiq Khan's decision to lower affordable housing thresholds to 20%, it generated the kind of headlines that sound alarming but often obscure what's really happening on the ground. But dig past the rhetoric and you'll find something more unsettling than the policy change itself: a building sector so broken that arguing over percentage points feels like rearranging deckchairs.
The row centres on the mayor's plan to ease affordable housing requirements for developers applying for fast-track planning approval. The councils claim this will mean fewer affordable homes. The mayor argues it's necessary to unlock stalled developments and get builders moving again. Both sides have a point, but neither is addressing why London's housebuilding has hit rock bottom.
The real issue isn't what's being built, it's that nothing's being built
Here's the uncomfortable truth: in a market where development has nearly stopped, arguing over what percentage of new homes must be affordable is almost academic. If no homes are being built at all, debating whether 20% or 35% of zero equals affordable housing becomes a distraction from the genuine crisis.
London's housebuilding rates haven't recovered since the financial crash. Large housebuilders are openly scaling back investment in the capital. When one major developer recently saw a scheme with just 12% affordable homes rejected twice, it signalled something deeper: the economics of London building simply don't work anymore, with or without strict affordable housing requirements.
This matters to everyone buying, selling or owning property in the capital. If developers aren't building, supply stays tight. With the UK average house price sitting at £270,080 and inflation at 2.8%, London prices aren't immune to broader supply constraints. Mortgages aren't getting cheaper either, with five-year fixed rates averaging 4.92%, making housing harder to access across all income levels.
What's actually changed and what hasn't
It's worth separating the policy change from what opponents claimed happened. The mayor hasn't cut affordable housing quotas so much as adjusted the threshold at which fast-track planning applications must include them. The councils are right that fewer schemes will be required to include affordable units, but the BBC's own reporting confused the issue by misreporting a 15 percentage-point change as a 15% cut. The sloppiness of the coverage itself tells you something about how muddled this debate has become.
The real effect? Some smaller schemes might now progress without providing affordable housing. Developers argue this removes a financial barrier that's stopped them building altogether. The councils contend it breaks a commitment to mixed-tenure development and abandons low-income Londoners. Both statements can be true simultaneously, which is part of why this is so difficult to solve.
The bigger picture for homeowners
For someone selling a London property right now, development stagnation is bad news. If the market isn't creating new housing supply, that typically props up prices for existing stock, but it also signals wider economic stress. For first-time buyers, fewer new schemes means competing harder for existing properties in an already squeezed market.
The uncomfortable reality is that London needs housing built at all income levels. The toughest nut to crack isn't the percentage of affordable units, but making the entire development proposition work financially. When viable schemes with 12% affordable housing are rejected twice, the problem isn't the affordability requirement. It's that the underlying economics have become broken.
Easing viable thresholds might sound like a step backwards on affordability, but a zero-percent completion rate on any housing is worse than a lower percentage of actual new homes. The councils filing for judicial review aren't wrong to worry about affordability. They're just potentially wrong about the solution.
What happens next matters more than who wins this argument
Whether the courts side with the councils or the mayor, London still faces the same core problem: developers won't build if the numbers don't stack up. That's a funding and cost issue, not a policy issue that can be fixed by arguing over percentage points.
If you're buying, selling or own property in London, watch for whether this legal challenge and its outcome actually shift the number of planning applications or development starts. That's the real measure of success, not which politician wins a rhetorical victory. Currently, housing supply remains constrained across London, and with mortgage rates holding steady at 4.92% for five-year fixes, the pressure on affordability isn't going anywhere.
The affordable housing debate matters. So does actually building homes. Right now, London's getting neither at the scale it needs.