The UK’s datacentre build-out is accelerating. Driven by the demand for artificial intelligence (AI) compute, and in the context of the government’s decision in 2024 to classify datacentres as critical national infrastructure, developers are racing to secure planning consent, grid connections and power across the country.
New analysis of Barbour ABI project data, compiled for Computer Weekly, shows that the committed datacentre pipeline – projects that have entered the planning system but have not yet completed – now stands at 173 projects and capacity of more than 14GW. That compares with a March snapshot of 114 projects and roughly 10GW, a rise of nearly 60 projects and about 4.5GW in six months.
The headline capacity of 14.6GW sits on top of a further 4.4GW of “pre-planning” projects – schemes that have been publicly floated but have not yet submitted a planning application. Together, the committed pipeline and the pre-planning tail represent close to 19GW of datacentre capacity working its way towards the UK’s power grid.
South East for volume; North for big projects
The regional picture is more nuanced than “everything moves north”.
London and the M4 corridor still dominate on volume. The region – stretching from the capital out through the Thames Valley and into South Wales – accounts for 82 of the 173 committed projects and 5.2GW, more than a third of total capacity. The home counties and the South East, a corridor running through Oxford, Cambridge and Milton Keynes, add a further 32 projects and 2.3GW.
But the scale of the projects tells a different story. The largest average scheme is in the North East, at 228MW per project – a region that contributes 1.6GW from just nine projects. Scotland averages 184MW per project across 14 schemes, while the M62 corridor averages 128MW across 23 projects. By contrast, the average committed project in London and the M4 corridor is 77MW.
More than half of the projects sit in the south, but the big, single-site campuses are increasingly in the North and Scotland. The pattern reflects the availability of large brownfield sites – former power stations and heavy-industrial land – together with access to high-capacity transmission infrastructure.
Rapid growth in Scotland
The fastest growth between March and September came in Scotland, where the committed pipeline rose from four projects and 0.9GW to 14 projects and 2.4GW – more than a threefold increase. The North East grew from six to nine projects, while the M62 corridor expanded from 18 to 23 schemes.
London and the M4 corridor added the most capacity in absolute terms – 52 projects in March to 82 in September, an increase of about 1.4GW – which reinforces its position as the largest market while the north and Scotland capture the largest individual developments.
The Midlands is relatively quiet, with just four committed projects totalling 66MW.
The methodology behind the data
The figures are drawn from three Barbour ABI datasets that track planning applications for datacentres – from March, June and September 2026 – that were analysed by Computer Weekly.
The pipeline identified comprises projects that have entered the planning system but are not yet complete. It excludes “built” projects in the data – 82 schemes totalling about 2.6GW that have finished, and which Computer Weekly will examine in a future article. It also excludes “pre-planning” projects – 24 schemes totalling 4.4GW that have been announced but have not yet entered the planning process (see “4.4GW that has not yet entered planning” section below for schemes announced but not yet committed to the planning system).
Capacity figures are derived as follows. Where a project’s megawatt figure is published in the Barbour ABI data, that figure is used. Where no capacity is published, the figure is estimated from floor area using a statistical model fitted to the projects that do publish both – a model that explains about three-quarters of the variance in published capacity (adjusted R² = 0.74). For nine significant projects with no published figure, capacity is estimated from press and trade reporting. The remaining projects – mostly small, edge or healthcare schemes – are counted in the project totals but carry no capacity figure, so the headline 14.6GW is a conservative lower bound.
This method is more complete than the one used in the Computer Weekly analysis in March. It therefore produces a higher March baseline of about 10GW, versus the roughly 8GW previously reported. The March-to-September comparison in this article applies the same method to both snapshots, so the growth figures are like-for-like.
The grid is the constraint
The trajectory points in one direction: a growing, increasingly northern pipeline of large datacentre campuses competing for a finite supply of grid connections and power.
As previous Computer Weekly analysis has documented, the government’s 2030 datacentre capacity targets already look ambitious. The shift of the largest schemes towards former power station sites in the North and Scotland reflects, in part, the search for land with existing transmission access – but it also raises the stakes for grid investment and for the communities hosting these projects.
The UK’s datacentre pipeline is growing, and it is growing fastest where the big sites and the big power connections already exist. The question is whether the grid can keep up.
4.4GW that has not yet entered planning
Beyond the 173 committed projects in the active pipeline, a further 24 schemes totalling about 4.4GW have been publicly announced but have not yet entered the planning system.
The list reads like a roll-call of the UK’s next hyperscale wave. It includes the 1GW campus planned for the former Cottam power station in Nottinghamshire, which is earmarked to be powered by small modular nuclear reactors; Digital Reef’s 600MW London Data Freeport on green belt land in Havering; the ILI Group’s “Stoics” trio in Scotland (Cato at 600MW, Rufus at 540MW and Aurelius at 400MW); Clearstone’s 300MW Ebbsfleet campus in Kent; and the 300MW SDC M40 scheme on a former landfill site in Buckinghamshire, backed by SDC Capital Partners and Veolia.
What distinguishes this group is how fast some of it is moving. Cato, Larbert and Spango Valley have all submitted planning applications since the September extract was compiled by Barbour ABI, while Ebbsfleet and SDC M40 are progressing through the nationally significant infrastructure project route. The boundary between “announced” and “in planning” is shifting quickly, and much of today’s pre-planning capacity is tomorrow’s committed pipeline.
For grid planners and the communities hosting these schemes, that is the central question. More than 4GW of announced datacentre capacity is queuing behind the 14.6GW already committed, and it is competing for the same finite supply of power connections.
Cottam: Small nuclear, but the reactors will lag behind the servers
The standout entry on the pre-planning list is the 1GW campus proposed for the former Cottam coal-fired power station in Nottinghamshire. In 2025, nuclear firm Holtec, energy group EDF and developer Tritax signed a memorandum of understanding to build Holtec’s SMR-300 small modular reactors (SMRs) on the site to power the new datacentres – potentially the UK’s first SMR-powered datacentre campus.
But the timeline tells the real story. Holtec’s SMR-300 design completed its Generic Design Assessment only in March 2026, and the joint proposal to government followed in June. Small modular reactors compress the decade-plus build of a large nuclear plant to roughly three to five years of construction, but the licensing and site works still point to first power around 2030 at the earliest, while the datacentre itself is targeted to come online sooner.
That means the servers are likely to arrive before the power. The campus would draw on the grid in the interim, with the SMRs following years later. For a project billed as “nuclear-powered”, the immediate reality is another large campus competing for grid connections, with its headline power source still years away.
