London has 26 additional data centres in its planning pipeline, but electricity connections could determine which developments reach construction first. A Government Office for Science report published on 12 November 2026 identifies grid delays as a major factor in deciding where new facilities can be built, while the London Assembly examined the capital's growing demand for power, water and industrial land on the same day. The new evidence comes as developers prepare projects across Hayes, Park Royal and other established London data-centre locations.
The Government Office for Science publication records an expert roundtable held on 20 February 2026, before several changes to national planning and electricity policy. Its findings are advisory, but they coincide with a detailed Greater London Authority study identifying 99 operational data centres, 26 further facilities in the planning pipeline and potential electricity connection waits of seven to 13 years. For London's construction industry, the opportunity now extends from the data halls themselves to the substations, cable routes, cooling systems and supporting infrastructure needed to make those developments operational.
Illustrative image of a data centre and substation under construction. Image: London Construction Magazine
London data centres in figures
99operational data centres in Greater London, November 2025
26further developments in the planning pipeline
7 to 13 yearsreported grid connection lead time in London
41GW to 125GWgrowth in Great Britain's demand connection queue
Sources: Buro Happold for the Greater London Authority, December 2025; Ofgem, 29 July 2026.
London's 26-project pipeline is a substantial construction opportunity
The Buro Happold study prepared for the Greater London Authority, dated December 2025, counted 99 operational data centres across Greater London in November 2025, with a further 26 developments in the planning pipeline. The study identified around 1GW of existing capacity, with possible growth to between 8GW and 11GW by 2050 under its longer-term scenarios.
LCM's comparison of the two site counts puts the planning pipeline at approximately 26% of the number of existing facilities. The 26 developments were at different planning stages when the study's data was compiled, and their eventual contribution to operating capacity will depend on individual project size, consent, financing and electricity supply. The 2050 figures describe growth scenarios based partly on network connection demand, not a construction programme already committed by developers.
Buro Happold identifies established concentrations around the Isle of Dogs, Park Royal and Hayes, with emerging development activity in outer boroughs including Barking and Dagenham. London's established fibre networks, access to major business customers and existing digital infrastructure provide reasons for operators to remain in the capital, although land availability and electricity capacity are changing the economics of individual sites.
Electricity is the principal constraint identified by the GLA study. It says new data-centre grid connections in London may require seven to 13 years, compared with three to seven years in other European markets. Those are reported connection lead-time ranges, not confirmed waits for every London development. Operators with existing capacity or secured connection arrangements can occupy a materially different position from developers entering the network queue.
The scale of that queue has already attracted regulatory action. Ofgem reported on 29 July 2026 that electricity demand connection applications across Great Britain had increased from 41GW to 125GW in less than a year, driven largely by data-centre projects. The regulator proposed commitment fees and stronger progression milestones to prevent speculative applications from occupying capacity that viable developments could use.
For construction companies, successful queue reform could improve visibility over which developments have a realistic route to energisation. That would make it easier to plan investment in electrical infrastructure, specialist labour and long-lead equipment without treating every announced data-centre campus as an imminent building contract.
Government science advice arrives after major planning changes
The Government Office for Science roundtable was chaired by Government Chief Scientific Adviser Professor Dame Angela McLean on 20 February 2026, bringing together representatives from Amazon Web Services, Pure Data Centres Group, techUK, BCS and four universities. Participants said that the UK lacked national planning guidance specifically addressing where data centres should be located and suggested creating an interactive map showing existing facilities, fibre routes and electricity infrastructure.
National planning policy has moved since that discussion. England's revised National Planning Policy Framework came into force on 17 August 2026 and strengthened provisions for data centres, associated electricity generation and network infrastructure. As LCM reported in its September 2026 examination of the NPPF, local planning authorities are now expected to consider the infrastructure needed to support data-centre development alongside the sites themselves.
The Government went further on 28 October 2026 by publishing a draft National Policy Statement for Data Centres. The document proposes a national decision-making framework for developments entering the Nationally Significant Infrastructure Project regime, using an indicative minimum threshold of 100MW of rated IT load for consideration under that route.
Entry into the NSIP process remains subject to the relevant statutory arrangements, including a direction under Section 35 of the Planning Act 2008. The draft National Policy Statement does not automatically transfer every development above 100MW away from the local planning system. It is under consultation until 8 January 2027 and has not yet been designated as national policy.
London is also developing its own approach. The draft London Plan, published on 16 July 2026, introduces Policy GLE3 for data centres. It asks boroughs to consider electricity and water availability, existing clusters, opportunities for heat recovery and the effects of development on housing, industrial land and freight activity. The proposed policy also addresses backup generation and its potential effects on local air quality.
Policy GLE3 remains part of a draft plan. The adopted national framework is already providing stronger support for digital infrastructure, while the detailed London and national policies continue through their respective planning processes. Electricity network connection and reinforcement programmes remain separate from those land-use decisions.
Policy timeline
20 February 2026Government Office for Science roundtable held
16 July 2026Draft London Plan published with Policy GLE3
29 July 2026Ofgem proposes commitment fees and progression milestones
17 August 2026Revised National Planning Policy Framework comes into force
28 October 2026Draft National Policy Statement and Data Centre Covenant published
12 November 2026Science report published; London Assembly committee session
22 December 2026Assembly's requested date for written evidence
8 January 2027Draft National Policy Statement consultation closes
Hayes shows why a grid date can shape the construction programme
Colt Data Centre Services provides a documented West London example. Its Hayes Digital Park expansion covers three additional hyperscale facilities, London 6, 7 and 8, together with an Innovation Hub. Colt announced a proposed £2.5bn investment in November 2025, with almost 100MW of additional IT capacity and a future campus total of around 160MW. The £2.5bn figure is a developer investment announcement, not an awarded construction contract.
LCM's review of Hillingdon Council's planning record 78343/APP/2025/719 on 12 November 2026 confirms hybrid planning permission dated 20 May 2026 for the Hayes Bridge Retail Park and Heathrow Interchange redevelopment. Phase 1 includes a data-centre building and associated power, water and site infrastructure, while later phases include additional data-centre buildings and the Innovation Hub.
A separate reserved-matters application, 78343/APP/2026/1746, for the Innovation Hub was still recorded as undecided when LCM checked the register on 12 November. It concerns the design and other reserved matters for Phase 2 and does not change the existing hybrid permission for the wider campus.
Colt's November 2025 project announcement said power contracts had been secured with National Grid, with high-voltage supply expected in October 2027 and the first new data centre scheduled to become operational in early 2029. Its programme illustrates how planning permission, high-voltage infrastructure delivery and commercial operation are separate milestones within one development.
For the specialist construction supply chain, those dates affect the sequencing of substations, transformers, switchgear, incoming cables, data-hall electrical distribution, cooling equipment and commissioning. Building fabric can progress through one programme while network energisation and operational testing follow another. The procurement strategy needs to account for both.
Park Royal shows the value of securing electricity early
SEGRO and Pure Data Centres Group offer another West London example through their joint venture at SEGRO Premier Park in Park Royal. The companies announced a development investment of approximately £1bn in March 2025, with Pure contributing 70MVA of secured electricity capacity to support a proposed 56MW IT-load data centre.
The two capacity figures describe different measures. The 70MVA relates to incoming electrical supply, while 56MW describes the proposed IT load. Treating the figures as interchangeable would overstate the computing capacity or obscure the electrical provision needed for cooling, distribution and supporting plant.
SEGRO confirmed planning committee approval in March 2026, while the development's formal planning permission was subsequently issued in July 2026 under reference 25/0196/FUMOPDC. The companies' original development arrangements envisaged construction proceeding after planning, leasing commitments and financing were secured. The site demonstrates the commercial advantage of an identified power supply while retaining the normal development and procurement stages.
The contrast with Hayes is useful for understanding London's pipeline. One developer has published a future high-voltage delivery milestone and phased operational programme. Another has reported secured incoming electrical capacity as part of a development intended for a hyperscale occupier. Neither model can be applied automatically to the other 26 facilities identified in the GLA's earlier pipeline study.
Two West London schemes compared
| Hayes Digital Park | SEGRO Premier Park, Park Royal | |
|---|---|---|
| Developer | Colt Data Centre Services | SEGRO and Pure Data Centres Group |
| Announced investment | £2.5bn, November 2025 | Approximately £1bn, March 2025 |
| Capacity | Almost 100MW additional IT capacity; campus total around 160MW | 56MW IT load; 70MVA secured supply |
| Planning | Hybrid permission dated 20 May 2026 | Committee approval March 2026; permission issued July 2026 |
| Power | High-voltage supply expected October 2027 | Electricity capacity secured before planning |
| Operation | First new data centre early 2029 | Not stated |
Sources: Colt DCS, SEGRO, Hillingdon Council and OPDC planning records. Investment figures are developer announcements, not awarded construction contracts.
Waste heat could become useful London infrastructure
The Government Office for Science report also examines the relationship between cooling, electricity demand and recovering waste heat. Participants considered water availability less of a national siting constraint than electricity, partly because cooling systems can operate with limited water use in the UK's climate. The report nevertheless identifies an engineering trade-off: reducing cooling water consumption can increase electricity requirements.
That distinction affects London development designs. Air-cooled or closed-loop systems may reduce demand on water supplies, but their electrical consumption must be included in the site's total power requirement. Cooling plant, heat rejection, acoustic protection and energy efficiency therefore need to be considered alongside the capacity available from the electricity network.
The same science advice says that exporting waste heat becomes more useful where a data centre is close to a district heating network or another customer able to use the heat. London already has examples of how that relationship can be considered through planning and infrastructure investment.
At Frogmore Industrial Estate in Park Royal, Old Oak and Park Royal Development Corporation's outline planning arrangements for a proposed data centre of up to 35,000 sq m include safeguarding for future district heating and cooling connections. The OPDC Section 106 record identifies the agreement dated 12 October 2022 for planning reference 21/0182/OUTOPDC.
The earlier OPDC planning committee record also identifies a £582,690 public-realm and healthy streets contribution and £36,000 towards air-quality monitoring, alongside employment, skills and heat-network commitments. These are planning obligations associated with the development, rather than evidence that every contribution has already been paid or every related facility constructed.
OPDC has separately investigated a data-centre waste-heat network in Park Royal. A published project decision records £315,000 secured in 2021 for technical feasibility and business-case work, including the possibility of supplying heat from the Frogmore area to nearby users such as NHS facilities. The proposal provides a documented route for examining heat reuse, although the feasibility funding does not establish that a complete district heating connection has been delivered.
These examples show how data-centre investment can support a wider construction programme. The opportunities extend to insulated heat-network pipework, energy centres, electrical reinforcement, utility connections and public-realm work, provided the relevant schemes have secured the necessary approvals and commercial arrangements.
Government's new deal could bring viable projects forward
The Government's Data Centre Covenant, published on 28 October 2026, introduces an offer of additional support for strategically important developments meeting specified expectations on electricity-system costs, environmental performance, local benefits, employment and national resilience.
For qualifying strategic projects, the Government proposes reserving or reallocating grid capacity, identifying additional power availability before 2030 and exploring transfers of existing connection contracts. It also intends to develop a controlled route for temporary on-site generation for exceptionally strategic developments where other connection measures cannot provide electricity in time.
These measures create potential construction work across electricity networks and on-site infrastructure. The Covenant also supports greater opportunities for developers to construct their own connection infrastructure, subject to network and consumer protections. LCM examined these measures in its earlier report on the 2026 Budget's data-centre grid connection proposals.
In return, strategic developers will be expected to provide local benefit plans, make credible commitments to electricity-system costs and meet environmental standards. The Covenant proposes new facilities designed to achieve a Power Usage Effectiveness of 1.3 or better, alongside efficient water use, annual reporting and waste-heat recovery where a viable local customer exists. The detailed strategic selection criteria and temporary-generation arrangements are still being developed.
For contractors, the most useful consequence would be greater confidence in which projects can proceed. The UK already has a substantial data-centre development pipeline, but a viable connection programme, a committed occupier and an agreed construction procurement route provide a firmer basis for tendering than an announced investment value. As LCM's September assessment of the £101bn national pipeline found, planning and investment announcements cover several stages of development and should not be counted as awarded construction work.
City Hall is examining the impact on Londoners
The London Assembly Environment Committee scheduled a public examination of data-centre impacts at City Hall on 12 November 2026, with separate panels covering community concerns and technical evidence from environmental and infrastructure organisations.
The Assembly's 11 November announcement identified representatives from Global Action Plan and campaigns in Park Royal and East Havering, alongside invited participants from the Environment Agency, Water UK, the Carbon Trust and the University of Exeter. The published agenda covered electricity demand, water consumption, air quality, noise, biodiversity and the effects of data-centre growth on nearby communities.
The committee's pre-meeting evidence establishes the subjects under scrutiny. Witness testimony from the 12 November session has not been attributed in this report because an independently checked transcript or recording was not available during LCM's review. The official committee agenda and broadcast record provide the route for reviewing the session and any subsequent findings.
London's approach needs to accommodate businesses that depend on reliable digital infrastructure while addressing the costs experienced by people living near large facilities. Electricity network upgrades must also be planned around housing, transport and other employment uses that compete for the same capacity. The Government Office for Science report specifically identifies transparency and credible local benefits as necessary for building community trust.
The Assembly has opened a call for evidence on the environmental impacts of data centres, inviting submissions from residents, organisations and people with relevant experience. The committee has requested written evidence by 22 December 2026 where possible. That provides an opportunity for London contractors, engineers, utilities specialists and residents to contribute evidence about how future developments could be delivered alongside the capital's wider infrastructure needs.
How LCM calculated this
LCM compared the 99 operational data centres and 26 planning-pipeline developments recorded in Buro Happold's December 2025 report for the Greater London Authority, using its November 2025 baseline. Dividing 26 by 99 produces approximately 26.3%, reported in this article as 26%. The calculation compares numbers of facilities within Greater London; it does not measure committed construction value, consented electrical capacity or the percentage increase in operational megawatts. LCM also checked the Hillingdon planning records for Hayes Digital Park on 12 November 2026 to distinguish the existing hybrid permission from the subsequent reserved-matters application.