CPRE London Joins “Dirty Data Centres” Action Days

Data centres need to be in the right place, with clear rules and high environmental standards.

Data centres are not a new phenomenon, and they’re not just about AI – they provide services for cloud computing, storage, and even server hosting for important infrastructure and industry. The Government has identified that in order to “protect national interests, and remain competitive” with the global AI market, there must be rapid expansion of domestic capacity.

London hosts the biggest concentration of data centres in Europe, and although they are currently clustered most heavily around Canary Wharf and surrounding boroughs, there has been an increase in the viability of larger, more intensive data centres in London’s outskirts due to changes in local and national planning policy.

Policy Breakdown

Following the recently restructured National Planning Policy Framework (NPPF) in August 2026, Policies E1 and E2 expect local planning to provide for data centres, their generating capacity, and the grid connections they need. While NPPF Policy GB6 considers development in the Green Belt inappropriate, exemptions can be made under GB7 where potential harm may be justified by national need, a lack of alternative sites, or economic benefits. Data centres have been identified by the Department for Business, Innovation, Science, and Trade as “mandatory infrastructure”, a sentiment that is echoed in the Draft New London Plan by policy GLE3. The Mayor of London has described data centres as the “only exception” to Green Belt restrictions. This is bolstered by Draft New London Plan recommendations that councils prioritise “grey belt” as prospective sites.

The Elephant in the Room: Environmental Impacts

In Slough itself, a large proportion of the town centre consists of data centre campus. Data centres within the town account for over 1GW of capacity across 30-40 operational facilities; capacity requirements have risen and are projected to reach almost 3GW by 2030. Keen to expand, developers have their sights on greenfield land on the town’s periphery.

Residents of Slough are feeling the heat in more ways than one. On the hottest days of 2026, weather stations near the campus recorded temperatures of a margin of 2°C hotter than the area’s average. Emerging research led by scientists at the University of Cambridge has defined the “data heat island” effect associated with data centre campuses, clusters, and associated enabling works: an observed temperature increase of an average of 2°C persisting up to 10km from the site. This heating compounds the effects of the urban heat island and adds additional heat stress to nearby habitats.

Proposals in the Treasury’s Data Centre Covenant suggest that the heat produced by data centres be used to warm nearby homes and schools wherever practical, but in a warming world with milder winters, there will be less and less use for excess heat.

Data centres are also incredibly thirsty, which becomes more pronounced during heatwaves as more water is needed to cool the hardware. Residents of London and the South East – already the UK’s driest region – have experienced what is projected to be the hottest, driest year on record. Droughts and periods of extreme anomalous heat will become longer and more frequent, and data centre freshwater consumption (which may draw from groundwater and potable sources if there are insufficient resources elsewhere) will place excess stress on an increasingly finite resource.

But the biggest toll by far is taken on energy resources. Within parts of West London, including areas encompassed by the Slough Availability Zone, housebuilding has been stalled due to shrinking availability of local energy capacity, attributed to quick and concentrated nearby expansion of data centres. Figures from the International Energy Association (IEA) show the energy consumption of a typical AI-focused data centre is the same as 100,000 households, but the largest hyperscale centres can consume up to twenty times more. Data centres can also be used to continuously store “dark data” – massive amounts of user data, the majority of which is never looked at yet never deleted. Still, the former CEO of National Grid estimated in March 2024 that “demand from commercial data centres will increase six-fold, just in the next ten years”.

What we asked from the London Plan

You can see our responses to the Draft London Plan here. On the new proposed data centre policy GLE3, CPRE London raised:

1. The policy should require whole-life carbon assessments and climate resilience assessments addressing embodied carbon, operational emissions, overheating, drought, water scarcity and future flood risk, together with cumulative and climate-adjusted assessments of electricity, water and infrastructure capacity for data centre clusters.
2. Given evidence that data centres already account for a significant proportion of UK electricity demand and are expected to increase consumption substantially over coming years, while also creating uncertainty around future water demand, the Plan must demonstrate that growth in the sector can be delivered sustainably without compromising London’s housing, environmental or infrastructure needs.
3. The policy should require meaningful early engagement with affected communities, transparency regarding electricity and water demand, and clear evidence of local economic, social and environmental benefits.

Without these amendments, GLE3 does not adequately address the cumulative impacts of data centre growth on climate resilience, natural resources, infrastructure capacity, environmental quality or community wellbeing, nor does it demonstrate that development will be delivered in the most sustainable locations.

We join CPRE in recognising that data centres are important infrastructure and support many aspects of our day-to-day lives. However, the frantic race to build new, hyperscale data centres does not mean they should be free from rules and regulations. There needs to be a strategic and enforceable plan to guide and monitor data centre development. Without this, we’re risking a barrage of unchecked data centre development, without scrutiny or community involvement, with potentially devastating impacts for nature, landscapes and farmland.

Data centres need to be in the right place, with proper rules and high environmental standards. No ifs, no buts. As part of the Stop Dirty Data Centres Action Days, we’re asking for a pause on unchecked data centre development until there’s a strategic plan for them. You can learn more about CPRE’s call to action and add your name to support here, keeping up with the team on the wider Draft National Policy Statement for Data Centres consultation here.