Why it matters
The strategic read
Adds a large UK sovereign-AI infrastructure lane to the Deal Room. The scarce inputs are bundled together: a permitted 85-acre London-adjacent site, 250+ MW of Equinix compute capacity, National Grid power reservation language from the planning approval, dry-cooling commitments, renewable-energy coverage and fiber / availability-zone proximity. It is not a signed AI customer contract, but it is a primary-source capex and site-control receipt for one of Europe’s largest AI-ready campuses.
Source-supported terms
What was disclosed
- 01
Equinix announced on October 30, 2025 that it completed the acquisition of an 85-acre plot permitted for data-center development in Hertfordshire, United Kingdom.
- 02
Equinix said it plans to invest £3.9B in the Hertfordshire Campus and deliver 250+ MW of compute capacity to the UK’s critical national infrastructure.
- 03
Equinix said the facility supports the UK’s sovereign AI ambition and will provide global, AI-ready infrastructure for sectors including healthcare, life sciences, public sector, financial services, manufacturing and entertainment.
- 04
The site was previously known as DC01UK and sits near South Mimms and the M25.
- 05
Equinix said construction is expected to directly generate 2,500 local jobs and more than 200 permanent roles once fully operational.
- 06
Equinix said European facilities, including the UK, are covered by 100% renewable energy and that Hertfordshire plans include dry cooling, 54% of land retained as open space and at least 10% biodiversity net gain.
- 07
Hertsmere Borough Council said on January 24, 2025 that its planning committee granted outline permission for the South Mimms data center on January 23, 2025.
- 08
The Hertsmere approval described DC01UK as Europe’s largest cloud and AI data centre when built, with up to 2M square feet of space.
- 09
The Hertsmere approval cited a 400 MVA National Grid power reservation, proximity to the Elstree / Letchmore Heath substation, proximity to national and international fibre optic routes, and nearby Availability Zones.
- 10
Hertsmere estimated construction value at £3.75B, with £21.4M in annual business rates once operational and about £1.1B per year of indirect GVA.
- 11
DCD reported on October 30, 2025 that Equinix had purchased the under-construction DC01UK facility, now called the Hertfordshire Campus, and that earlier plans had targeted 320 MW before Equinix framed the campus as 250+ MW.
- 12
The Deal Room classifies this as an older-source, newly surfaced gap because the July 2026 scan found it missing from the current archive; it is not a same-day July 2026 announcement.
Disclosure boundary
What is known—and what is not
Primary Equinix announcement, primary Hertsmere planning-approval release and DCD near-primary coverage. Public materials disclose Equinix site acquisition completion, £3.9B planned investment, 85-acre campus, 250+ MW compute capacity, DC01UK predecessor, outline planning approval, 400 MVA power reservation language, fiber / availability-zone proximity, renewable-energy and dry-cooling commitments, open-space / biodiversity plan, construction and permanent job estimates, and high-level economic-impact estimates. Public materials do not disclose the purchase price, full acquisition agreement, customer leases, financing stack, reserved-matters approvals, construction/EPC awards, utility service agreement, PPA pricing, phased energization schedule, server or GPU allocation, full network contracts, tenant mix, remedies, cancellation rights or whether all planned future capacity is committed today.