UK’s top 10 Proposed AI Data Centres by Site Size
It’s official. Frankenstein’s monster is out to destroy humanity unless Donald Trump saves us! Before it does, let’s look at the ten largest AI Data Centres proposed in the UK.
Dario Amodei (Anthropic), Sam Altman (OpenAI) and Elon Musk (xAI) have all issued statements acknowledging the potential for AI to go rogue after Jacob Coxon left Anthropic on September 8th to blow the whistle.
In 2025, a statement calling for a ban on the development of superintelligence was signed by hundreds of public figures including AI experts, five Nobel Prize laureates, and former senior US national security officials.
Will this slow the slew of applications to build AI Data Training Centres? Apparently not. Below is a list of the 10 largest in order of site size in the UK as of September 2026. Precise information is not necessarily available yet, so we have referred to planning applications and official statements.
Also, some figures refer to the total campus footprint, not purely the data centre floor area. Some developments include ecology parks, substations and landscaping to soften the impact on the surrounding area. We have tried to indicate where this is the case.
- East Havering Data Centre Campus — Havering, East London
Applicant: Digital Reef Limited (part of Reef Group)
Site area: 218 hectares / 539 acres (total campus including 113-hectare ecology park)
Data centre floor area: Up to 340,000 m² (3.66 million sq ft)
Power capacity: Up to 600 MW
Investment: £14.7 billion
Status: Local Development Order process underway; public consultation completed April 2026
Notes: Proposed on green belt land at the boundary of Havering and Thurrock, east of the M25 on Fen Lane and Dunnings Lane, North Ockendon. The campus includes 12 data centre buildings, 113 hectares of public ecology park, heated greenhouses, BESS, and educational facilities. Construction window targeted from 2026 to 2046.
- Elsham Tech Park — North Lincolnshire
Applicant: Greystoke (Elsham Tech Park Limited)
Site area: 176 hectares / 435 acres
Data centre floor area: Up to 1.5 million m² (16.1 million sq ft) at full build-out
Power capacity: Up to 1 GW
Investment: Up to £10 billion
Status: Outline planning permission granted by North Lincolnshire Council, March 2026
Notes: Located on and adjacent to the former RAF Elsham Wolds airfield near the Elsham Wolds Industrial Estate, part of the Northern Lincolnshire AI Growth Zone. Plans include 15 hyperscale data halls, an on-site 49.9 MW energy centre, BESS compound, district heating plant, and greenhouse horticulture using waste heat. Construction expected to begin 2027; first phase to open 2029.
- QTS Cambois Campus — Cambois (near Blyth), Northumberland
Applicant: QTS Realty Trust (owned by Blackstone)
Site area: 153 hectares / 378 acres (total site); Phase A enabling works on 54 hectares
Data centre floor area: 540,000 m² (5.8 million sq ft) across 10 buildings
Power capacity: 720 MW substation; each building 72 MW IT capacity
Investment: Up to £10 billion
Status: Outline planning permission granted March 2025; Phase A reserved matters approved December 2025; site works underway
Notes: Located on the former Blyth Power Station site at Cambois. Ten three-storey data halls, each 54,000 m², with a closed-loop water-free cooling system. Includes a £110 million community economic fund for Northumberland County Council. First phase targeted for completion 2029; full build-out by 2035. Planning consultant: Quod; architect: Corgan.
- Digital Reef / Reef Origin — Didcot, Oxfordshire
Applicant: Reef Group (Digital Reef / Reef Origin)
Site area: 50 hectares / 124 acres
Data centre floor area: Up to 110,000 m² (1.18 million sq ft) across 6 build zones
Power capacity: Not yet published
Investment: Not yet confirmed
Status: Planning application filed April 2025
Notes: Located at Hill Farm, Didcot, on a former industrial/agricultural site near the former Didcot Power Station. Includes BESS, ecology zone, and zero fossil fuel on-site commitment. Positioned to leverage proximity to the Didcot grid infrastructure corridor.
- DC01UK / Equinix Hertfordshire Campus — South Mimms, Hertsmere, Hertfordshire
Applicant: DC01UK (joint venture between Chiltern Green Energy and Griggs Homes); subsequently sold to Equinix, October 2025
Site area: 85 acres / 34 hectares
Data centre floor area: Up to 186,000 m² / 2 million sq ft across 3 buildings
Power capacity: 400 MVA power reservation (National Grid, Elstree substation)
Investment: £3.9 billion (Equinix acquisition and development)
Status: Outline planning permission granted by Hertsmere Borough Council, January 2025; detailed application pending
Notes: Located on green belt land east of South Mimms Services, adjacent to the A1/M25 junction. Close to existing fibre optic routes and multiple London Availability Zones. Pitched as Europe’s largest cloud and AI data centre by floor area. Waste heat proposed to supply local homes. Construction targeted from 2027; operational from 2029.
- Manor Farm Data Centre — Heathrow (Slough Availability Zone), London
Applicant: Tritax Big Box REIT Limited (in JV with a European renewable energy generator)
Site area: 74 acres / 30 hectares
Data centre floor area: Phase 1: 41,600 m² (448,000 sq ft); total phases: up to 147 MW
Power capacity: 107 MW (Phase 1); 147 MW (both phases)
Investment: Not formally disclosed; site acquired January 2025
Status: Planning application for Phase 1 submitted; determination expected H2 2025; construction commenced H1 2026
Notes: Located at Manor Farm, in the Slough Availability Zone adjacent to Heathrow Airport, one of the prime FLAP-D (Frankfurt, London, Amsterdam, Paris, Dublin) European data centre markets. Grid connection secured via JV partner’s pre-existing agreements, bypassing a queue that would otherwise have taken over 10 years.
- TBC Partners Blyth Data Centre — Cambois, Northumberland
Applicant: TBC Partners
Site area: 12 hectares / 29.6 acres
Data centre floor area: Not yet published
Power capacity: Up to 300 MW
Investment: Not yet disclosed
Status: Pre-application screening opinion requested August 2026; full application not yet submitted
Notes: Located off Factory Road, Cambois, near the A189 and River Wansbeck — immediately adjacent to the QTS Cambois campus. Proposed as one or two main data centre buildings with on-site substation. Construction intended 2028–2030; occupation and operation 2030–2035.
- Apatura Motherwell Data Centre — Motherwell, North Lanarkshire, Scotland
Applicant: Apatura (through subsidiary Apatura DC Project 7 Limited)
Site area: Approximately 16.5 hectares / 41 acres
Data centre floor area: Not yet confirmed
Power capacity: Not yet confirmed
Investment: Not yet disclosed
Status: Announced June 2025; planning application in progress
Notes: A hybrid development combining a large-scale BESS with data centre facilities — one of the first such co-located projects in the UK. Positioned to benefit from Scotland’s available grid capacity and favourable planning environment for data infrastructure.
- Reef Group Technology and Data Centre Park — Hill Farm, Didcot, Oxfordshire (second Reef Group project)
Applicant: Reef Group
Site area: 23 hectares / 56.8 acres
Data centre floor area: Up to 110,000 m² (1.18 million sq ft)
Power capacity: Not yet published
Investment: Not yet disclosed
Status: Planning application filed April 2025
Notes: A separate Reef Group project to the larger Didcot/Reef Origin campus listed above, also at Hill Farm. Includes BESS component alongside data centre development. (Some sources conflate the two Didcot projects; they are listed here as reported in Data Centre Dynamics as distinct filings.)
- Iver Data Centre — Iver, Buckinghamshire
Applicant: Not publicly confirmed at time of writing
Site area: 16.5 hectares / 41 acres
Data centre floor area: Up to initial phase of 48 MW IT capacity
Power capacity: 48 MW (Phase 1); 150 MW substation
Investment: Not yet disclosed
Status: Planning application submitted; determination pending
Notes: Located east of the M25 on Slough Road (A4007), south of the Iver Substation — a highly strategic grid connection point in one of the UK’s most constrained but most sought-after data centre markets. The proximity to established Slough and Heathrow Availability Zones makes this site especially attractive for latency-sensitive hyperscale operators.
Please note: This list is accurate as of mid-September 2026.
Passage through the UK data centre planning pipeline is moving extremely fast. New applications are being filed monthly as competitive investors identify potential sites. This means several major projects, such as a reported Microsoft campus in Wales and Amazon applications all over the UK, do not feature here because they do not appear in formal planning records.
While protesters protest, what indebted Government would not want to benefit from the tax revenue and infrastructure investment these vast projects bring?
