London's data centre construction boom is moving into a harder phase. Major schemes are progressing across Docklands, Brent Cross, Hayes, Park Royal, Dagenham, Iver and the wider Slough corridor, but the question entering 2027 is no longer simply how much capacity developers want to build. It is which projects can secure power, mobilise contractors, procure long-lead electrical equipment and move from planning approval into physical delivery.
That distinction matters because the headline pipeline is enormous. City Hall's latest evidence puts London's existing data centre capacity at around 760MW across 99 sites, while more than 8GW is already sitting in the electricity connections queue. At the same time, new hyperscale campuses are being designed around artificial intelligence, cloud and high-density computing workloads that make electrical infrastructure, cooling and commissioning increasingly dominant parts of the construction programme.
This builds on LCM's wider analysis of London's data centres as critical digital and power infrastructure. The 2027 pipeline shows the next stage of that shift: developers are still committing billions of pounds to London and its surrounding availability zones, but delivery is separating into schemes with secured infrastructure and schemes that remain commercially attractive on paper without yet having all the ingredients needed to build.
While headline planning approvals suggest an expanding London data-centre pipeline, London Construction Magazine analysis shows that secured electricity capacity, energisation timing and proven construction mobilisation now determine which schemes can actually convert into 2027 workload.
The 2027 Pipeline: What Is Actually Moving
The project picture below deliberately separates physical construction from approval, procurement and pre-construction. Capacities are reported as publicly stated and are not always directly comparable: some developers disclose IT load in MW, others incoming electrical capacity in MVA, and others wider campus totals.
| Project | Status at 8 Aug 2026 | Power / Scale | Delivery Team | 2027 Construction Signal |
| Ada Infrastructure Docklands Royal Docks, Newham |
Under construction. Groundbreaking confirmed February 2026. | 210MW campus across three 70MW buildings. | McLaren Construction on the first 70MW phase, with specialist piling, civils, steel and engineering packages. | One of the clearest confirmed sources of major London data-centre construction workload through 2027. First building targeted for service in mid-2028. |
| Pure DC Brent Cross North London |
Operational campus with further phase under construction. | Around 90MW campus capacity reported across phases. | Glencar appointed on the latest phase; Mace has delivered earlier cold-shell work. | Continued construction into the later 2020s gives North London a significant live mission-critical programme rather than a planning-only pipeline. |
| Colt Hayes Digital Park Expansion Hayes, Hillingdon |
Approved. Construction was scheduled to begin during 2026; physical progress on London 6–8 should be checked against site activity as the programme advances. | 97MW expansion, taking the campus to 160MW. | Main construction contractor for the expansion not publicly confirmed in the evidence reviewed. | High-voltage supply is expected by October 2027, making grid delivery itself one of the programme's most important milestones. London 6 is targeted to go live in early 2029. |
| SEGRO / Pure DC Premier Park Park Royal, West London |
Planning committee approval secured in March 2026; pre-construction and customer discussions continuing. | 70MVA incoming power disclosed by SEGRO. | SEGRO / Pure Data Centres Group joint venture; main contractor not yet confirmed publicly. | A major test of whether approved, power-positioned West London capacity converts into a fully mobilised build programme. |
| Court Lane Data Centre Campus Iver, Buckinghamshire |
Predevelopment and enabling phase, with a complex planning, remediation and utility interface. | Up to 140MW IT capacity with major dedicated electrical infrastructure. | McLaren Construction with Phoenix ME on the MEP delivery pathway. | 2027 should show whether brownfield remediation, major utility diversion and power infrastructure convert successfully into the main construction programme. |
| Bidder Street Data Centre Canning Town, Newham |
Approved and progressing through procurement / pre-construction in the latest evidence reviewed. | 80MW IT capacity; reported development investment around £750m, with construction cost figures reported separately. | Legal & General, Goldacre and sineQN associated with the scheme; main contractor appointment was not confirmed in the evidence reviewed. | A previously reported early-2027 operational target now places significant pressure on contractor appointment, mobilisation, MEP delivery and commissioning sequencing. |
| NTT London Expansion Dagenham, East London |
Further campus construction active around the LON1 expansion programme. | Existing and expanding mission-critical campus supported by major on-site electrical infrastructure. | Public reporting identifies different contractors across phases and packages; this tracker does not assign one contractor to the entire programme. | Reinforces Dagenham and East London as an established alternative delivery cluster rather than merely a future planning opportunity. |
| Equinix LD14 Slough Trading Estate |
Under construction and approaching its reported 2026 completion window. | Around 30MW IT capacity and approximately 15,100 sqm reported. | Laing O'Rourke. | Provides an important counterpoint to the power-constraint narrative: the M4 corridor can still deliver major capacity where land, approvals and electricity have already been secured. |
The table should not be read as a forecast that every listed scheme will deliver on its publicly stated programme. It is a construction-status snapshot. That distinction is increasingly important in a market where planning permission, electricity reservations, customer commitments, contractor mobilisation and final energisation can all sit on different timelines.
Power Has Become the Real Development Gate
The strongest evidence behind the 2027 pipeline is not a single construction contract. It is the scale of London's electricity queue. City Hall reported in June 2026 that London already hosts around 99 data centre sites using approximately 760MW at peak demand, while more than 8GW of additional demand is sitting in the electricity connections queue. That means proposed demand is already more than ten times the capacity used by London's existing data-centre estate.
The problem is wider than London. Ofgem reported on 29 July 2026 that contracted electricity demand offers had increased from 41GW to 125GW in under a year, with at least 80GW attributed to data-centre projects. The regulator is now consulting on a specific data-centre commitment fee and new progression milestones designed to remove speculative projects from the connections queue and give viable schemes a better chance of progressing.
Those proposed milestones are unusually relevant to construction. Ofgem wants developers to demonstrate a credible end user, procurement of long-lead electrical equipment such as switchgear, and sufficient financial and technical capability to deliver. In practical terms, the electricity regulator is moving closer to testing the same question construction teams already face: is this a genuine project with a deliverable programme, or a grid reservation attached to a speculative development?
LCM previously examined why National Grid constraints are increasingly affecting construction starts. Data centres push that issue to its extreme because electrical connection is not simply one package within the build. It determines the commercial usefulness of the finished asset.
London Is Becoming a Two-Speed Data Centre Market
West London remains one of Europe's most important data-centre locations. Hayes, Park Royal, Slough and the Iver corridor combine fibre connectivity, established cloud availability zones, major enterprise demand and a mature mission-critical supply chain. The problem is that the same concentration has placed exceptional pressure on electricity infrastructure. New schemes therefore have to prove not simply that the location is commercially desirable, but that enough electrical capacity can be delivered on a programme that aligns with construction.
This does not mean West London has stopped. Equinix LD14 is a visible example of major capacity being physically delivered in Slough. Colt has secured electricity arrangements for its Hayes expansion and expects high-voltage supply by October 2027. Premier Park has disclosed 70MVA of incoming power. The more accurate conclusion is that West London is becoming selective: projects with secured or credible power pathways can progress, while projects without them face a much harder route from planning to mobilisation.
East London is consequently becoming more important. Ada's 210MW Docklands campus has moved into physical construction in the Royal Docks, while Dagenham already supports substantial NTT infrastructure and Newham has further approved capacity in the pipeline. The emerging geography is therefore not a simple migration from west to east. It is a two-speed market in which development follows the locations where power, land, fibre, planning and programme can still be aligned.
The draft 2026 London Plan now reflects that reality directly. Its proposed data-centre policy asks planning authorities to consider current and projected electricity and water capacity, impacts on housing and other infrastructure, opportunities for clustering and heat recovery, and the environmental impact of backup generation. Data-centre planning is therefore moving beyond the building footprint and towards the infrastructure system that has to support it.
The Contractors Winning Work Are Following the Power-Critical Path
The visible delivery pipeline is already concentrating specialist experience among a relatively small group of contractors. McLaren Construction is delivering the first 70MW building at Ada Docklands and is also involved in the predevelopment pathway at Court Lane. Glencar is active at Pure DC Brent Cross. Laing O'Rourke is delivering Equinix LD14. Phoenix ME appears in major hyperscale MEP delivery, while specialist civils, piling, steel, electrical and commissioning firms sit below the main contracts.
This matters because data-centre procurement is not equivalent to conventional office construction. The shell can progress while the most important programme exposures sit elsewhere: high-voltage connections, substations, transformers, switchgear, generators, UPS systems, cooling plant, controls integration, fire protection, security and integrated systems testing. A structurally complete data centre that cannot be energised, commissioned and proven under load is not commercially complete.
The contractor opportunity is therefore significant but demanding. Data-centre programmes create work for remediation, demolition, earthworks, foundations, structural steel, concrete, roofing and envelope specialists, but the real competitive pressure intensifies around electrical infrastructure, MEP management and commissioning. Long-lead procurement can move ahead of visible site activity, meaning supply-chain commitment may have to occur before a scheme looks like a major construction project from the outside.
The 140MW Court Lane campus at Iver illustrates that sequencing problem clearly. Before the main hyperscale structures can be treated as straightforward vertical construction, the programme has to deal with brownfield conditions, major utility diversions, power infrastructure and specialist MEP coordination. On projects of this scale, the critical path can begin below ground or outside the building boundary.
The 2027 Risk Is Approval Without Energisation
The most important distinction for contractors, consultants and suppliers entering 2027 is between an approved data centre and a deliverable data centre. Planning approval confirms that a scheme can progress through the planning system subject to its conditions. It does not automatically confirm the final grid connection, the electrical equipment programme, the customer commitment, funding maturity, contractor appointment or integrated commissioning sequence.
That gap explains why some headline completion dates should be treated cautiously. Bidder Street has been associated with an early-2027 operational target, yet the latest evidence reviewed still places the project around procurement and pre-construction rather than a mature physical build. Premier Park has planning committee approval and significant incoming power but is still progressing customer and delivery arrangements. Colt's Hayes expansion is strategically strong, yet the disclosed high-voltage supply date of October 2027 shows how electrical infrastructure can sit years ahead of operational completion.
For commercial teams, this changes how pipeline should be valued. A £1bn announcement is not necessarily £1bn of immediately accessible construction workload. A 100MW planning consent is not necessarily a 100MW project starting next quarter. The most valuable signals are increasingly physical mobilisation, contractor appointment, utility works, substation construction, equipment orders, energisation milestones and customer commitments.
That is also why Ofgem's proposed queue reforms matter beyond the electricity industry. If developers must increasingly prove commercial maturity and real procurement progress to retain scarce grid capacity, speculative schemes could be separated from executable projects earlier. That may ultimately make the visible construction pipeline smaller on paper but more reliable in practice.
What the 2027 Pipeline Actually Tells the Construction Market
Is London running out of capacity for data centres? Demand is substantially ahead of available electricity infrastructure, but that does not mean construction has stopped. The market is becoming more selective, with power-secured projects gaining an increasingly important delivery advantage.
Where is the strongest construction activity? West London, Slough and the M4 corridor remain critical because of their established connectivity and cloud ecosystems, while Royal Docks, Newham and Dagenham are strengthening East London's role. The dividing line is increasingly infrastructure deliverability rather than geography alone.
What should contractors watch? Contractor appointments, enabling works, grid milestones, substations, transformer and switchgear procurement, cooling strategy, customer pre-commitment and commissioning dates now give a more reliable picture of genuine workload than planning permission by itself.
The full contractor implications, sequencing risks and mitigation strategies are included in today’s London Construction Magazine briefing.
Evidence-Based Summary
London's data-centre pipeline remains one of the strongest specialist construction markets entering 2027, but its scale cannot be understood from planning approvals alone. Electricity connections, power infrastructure, long-lead MEP procurement, customer commitment, contractor capacity and commissioning now determine whether approved megawatts become physical construction workload. West London remains strategically important where power has already been secured, while East London is gaining weight through major live schemes such as Ada Docklands and the established Dagenham cluster. The opportunity is substantial, but the most valuable pipeline intelligence will come from tracking physical delivery evidence rather than headline development announcements.
Source Context and Editorial Note
This analysis uses project and market evidence available up to 8 August 2026. Key primary and developer sources include the Greater London Authority's data-centre growth evidence, Ofgem's July 2026 data-centre connection reform proposals, Ada Infrastructure's Docklands construction update, Colt DCS's Hayes expansion programme and SEGRO's Premier Park project update.
Project capacities, electrical capacities and financial values should not be treated as directly interchangeable. Public disclosures can refer to IT load, incoming electrical capacity, total campus capacity, development investment or individual construction packages. Where contractor appointments, construction starts or energisation dates were not sufficiently clear in the evidence reviewed, this article has deliberately avoided presenting them as confirmed facts.
Data-centre programmes are fast-moving and individual project dates may change as planning conditions, customer commitments, grid connections, contractor procurement and technical design develop. This article is construction market analysis and does not constitute planning, engineering, electrical, investment, procurement or commercial advice.
| Expert Verification & Authorship: Mihai Chelmus Founder, London Construction Magazine | Construction Testing & Investigation Specialist |
