Summary
- London’s draft plan would allow data centres on some grey belt land where wider policy tests are met.
- Schemes would need to address electricity demand, water efficiency, cooling technology, renewables, and waste heat recovery.
- The proposal widens the land debate while leaving grid availability and local consent as central delivery constraints.
The Greater London Authority has proposed planning policy that would allow data centres on parts of London’s grey belt, provided schemes can satisfy infrastructure and environmental requirements around power, water, cooling, renewables, and waste heat.
The measure appears in the draft London Plan, which is out for consultation until 15 October 2026. Data centres are treated as a distinct infrastructure use within the plan’s approach to green belt and grey belt land, reflecting the pressure to accommodate digital infrastructure in a city with limited industrial land and deep demand.
The draft plan does not create an automatic route through planning. Developments would need to address electricity demand, coordinated heat recovery infrastructure informed by a waste heat utilisation plan, electricity and water efficiency measures, innovative cooling technologies, and opportunities for on-site or nearby renewable energy. The draft chapter is available through the London Plan consultation.
Land release meets grid constraint
London remains one of Europe’s most important data centre markets, supported by finance, cloud, carrier, enterprise, and public-sector demand. The harder problem is physical capacity. Land availability, grid connections, substation delivery, cooling requirements, and local planning scrutiny increasingly define whether demand can be converted into new supply.
The grey belt proposal marks a shift in how data centres are being described in planning policy. They are no longer treated only as commercial buildings with unusual electrical loads. The draft plan ties them directly to electricity networks, water systems, heat recovery, and the city’s wider economic infrastructure.
That is a more realistic framing. A large data centre is a power project, a cooling project, a construction project, and a local infrastructure intervention. Its impact does not stop at the building envelope. It reaches substations, backup generation, fuel logistics, water demand, heat rejection, access roads, and the network corridors that connect it to customers.
Grey belt policy may give developers more site options, but the electrical route remains the harder gating item. A site can become more acceptable in land-use terms while still being commercially weak if the grid connection date is distant or if reinforcement costs are prohibitive. London’s power constraints will not be solved by changing land classification alone.
Heat and water move into planning detail
The waste heat requirement is likely to draw particular attention. London has the density and heat demand that can make data centre heat recovery more credible than in many dispersed markets, but practical delivery remains difficult. Heat networks need compatible temperatures, nearby users, financeable connections, and long-term operational agreements.
Water and cooling conditions will also become more prominent as AI workloads increase rack densities. New facilities may use liquid cooling, hybrid plant, closed-loop systems, or different heat rejection strategies from older colocation sites. Planning authorities are beginning to look at those operating characteristics rather than leaving them as technical details for later design stages.
Local opposition will still be a decisive factor. Data centres can be described as critical digital infrastructure, but host communities often judge projects by construction disruption, limited permanent employment, noise, diesel backup generation, visual impact, and pressure on local infrastructure. A grey belt route may intensify that scrutiny if sites move closer to contested land.
The draft policy leaves London with a narrow balance to manage. It needs digital infrastructure, but it also needs homes, logistics land, green space, power capacity, water resilience, and heat networks that actually function. Data centre development will have to prove it can fit into that wider infrastructure system.
The consultation will test how far London is prepared to adjust land policy for digital capacity. The answer will still depend on whether developers can show credible power, efficient cooling, measurable heat use, and a local infrastructure case that survives examination beyond the site boundary.
