Operating

Ark Longcross Park

Chertsey, Surrey, United Kingdom

Reviewed 27 Sept 20267 sources

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Project brief

Operating Nebius-hosting campus with traced phase-one delivery and consultant team. Contractor 16.8 MW phase-one and consultant 54 MW two-building design scopes are separate from unverified utility import.

Read overview

Current evidenceOperating

7 cited sources · 7 utility and planning categories reviewed.

Review evidence and gaps

Next check

Retrieve RU.13/0856 and RU.21/0780 signed decisions, approved Ark red lines and discharge records; check subsequent variations and distinguish the data-centre parcel from the wider Garden Village.

Open the full check

Overview

Developer / applicant: Ark Data Centres
Owner: Not verified
Operator: Ark Data Centres

Planning and delivery status

Ark’s February 2026 update describes delivery and commissioning of Nebius AI infrastructure at Longcross.

Stage source: 16 Feb 2026

Project intelligence. This record does not establish that the land or facility is available to acquire.

POWER STUDY

Power

What the power evidence establishes

The site-specific connection scope has not been established for this record.

Power classDNo qualifying rung

No same-scope, dated import-MVA rung has document-seen or better verification. Nearby infrastructure, IT MW and marketing claims cannot upgrade the class.

The class describes published documentary evidence at its stated date. It does not prove current contractual rights, transferability or an energisation date.

Class describes evidence maturity. Public records do not prove current contractual rights, transferable capacity or an energisation date. This record has not received a complete power study review.

Read the rules and verification levels

Capacity ladder and evidence

Each rung is a separate MVA claim for its stated site or phase. A missing rung is unknown.

Applied

Unknown

Not established from the public records reviewed.

What applied mva is evidenced for the assessed site scope?

Event date

Unknown

Not established from the public records reviewed.

What is the effective date of the applied connection evidence?

Capacity boundary

Unknown

Not established from the public records reviewed.

Which buildings or phases does the applied connection evidence cover?

Verification

Unknown

Offered

Unknown

Not established from the public records reviewed.

What offered mva is evidenced for the assessed site scope?

Event date

Unknown

Not established from the public records reviewed.

What is the effective date of the offered connection evidence?

Capacity boundary

Unknown

Not established from the public records reviewed.

Which buildings or phases does the offered connection evidence cover?

Verification

Unknown

Accepted / contracted

Unknown

Not established from the public records reviewed.

What accepted or contracted mva is evidenced for the assessed site scope?

Event date

Unknown

Not established from the public records reviewed.

What is the effective date of the accepted connection evidence?

Capacity boundary

Unknown

Not established from the public records reviewed.

Which buildings or phases does the accepted connection evidence cover?

Verification

Unknown

Energised

Unknown

Not established from the public records reviewed.

What energised mva is evidenced for the assessed site scope?

Event date

Unknown

Not established from the public records reviewed.

What is the effective date of the energised connection evidence?

Capacity boundary

Unknown

Not established from the public records reviewed.

Which buildings or phases does the energised connection evidence cover?

Verification

Unknown

Connection point and load boundaries

Network operator: Unknown
Not established from the public records reviewed.
Which TSO or DSO is responsible for this demand connection?
Connection point: Unknown
Not established from the public records reviewed.
What is the operator-confirmed connection substation or circuit?
Voltage: Unknown
Not established from the public records reviewed.
What voltage level is specified for the demand connection?
Straight-line distance: Unknown
Not established from the public records reviewed.
What are the evidenced site and connection-point coordinates, and their calculated straight-line distance?
Published route length: Unknown
Not established from the public records reviewed.
What grid route length is published, and for which circuit?

IT load

Unknown

Not established from the public records reviewed.

What is the published IT load in MW?

Basis

Unknown

Not established from the public records reviewed.

On what electrical basis is the IT load in MW stated?

Site / phase boundary

Unknown

Not established from the public records reviewed.

Which phase or campus does the IT load in MW cover?

Facility load

Unknown

Not established from the public records reviewed.

What is the published facility load in MW?

Basis

Unknown

Not established from the public records reviewed.

On what electrical basis is the facility load in MW stated?

Site / phase boundary

Unknown

Not established from the public records reviewed.

Which phase or campus does the facility load in MW cover?

Import capacity

Unknown

Not established from the public records reviewed.

What is the published import capacity in MVA?

Basis

Unknown

Not established from the public records reviewed.

On what electrical basis is the import capacity in MVA stated?

Site / phase boundary

Unknown

Not established from the public records reviewed.

Which phase or campus does the import capacity in MVA cover?

These are different electrical quantities. No power factor, PUE or available import is assumed from an IT-load statement.

Connection agreement and conditions

Agreement type: Unknown
Not established from the public records reviewed.
What connection agreement type and current status are documented?
Phased capacity: Unknown
Not established from the public records reviewed.
Does the agreement impose phased import-capacity limits?
Flexibility obligations: Unknown
Not established from the public records reviewed.
What flexibility or curtailment obligations apply?
On-site generation obligations: Unknown
Not established from the public records reviewed.
What on-site generation obligations apply?
Securities posted: Unknown
Not established from the public records reviewed.
What securities are required, posted and still valid?
Longstop dates: Unknown
Not established from the public records reviewed.
What connection longstop or milestone dates apply?

Conflicts and scope comparisons

No conflicting pair is recorded. This does not establish that all public statements have been reconciled.

United Kingdom grid context

Network publications frame the claim. They do not allocate capacity to this site.

No country context entries have been linked to this site. Applicable policy, capacity information and reinforcement dependencies need review.

Country coverage: prepared sources; site-level research not extended. View all country sources and refresh schedules.

Derived energisation window

Earliest plausible yearUnknown

Latest plausible yearUnknown

The observed inputs do not establish a bounded delivery range. Open bounds stay unknown.

Rule

Use only a same-scope, dated, document-verified capacity rung and an applicable duration to energisation published by the observed site operator. The named process operator and a named source publisher must match that operator. Earliest year is the maximum of stage date plus minimum duration and each evidenced readiness constraint. Latest year is the maximum of stage date plus maximum duration and each published upper constraint only when every required input is bounded. An offer-processing duration is excluded. A missing required input leaves the affected bound unknown; no padding or contractual delivery promise is inferred.

No observed inputs establish this result.

Dependencies driving the range

Connection-dependent reinforcement scope and completion dates: unknown.
Grid-works planning status and programme: unknown.
Applicable connection-policy conditions and programme: unknown.

What the earliest case requires

Connection-dependent reinforcement scope and completion dates introduces no later constraint than the earliest case; this remains unverified.
Grid-works planning status and programme introduces no later constraint than the earliest case; this remains unverified.
Applicable connection-policy conditions and programme introduces no later constraint than the earliest case; this remains unverified.

Missing inputs leave the range open

A dated, document-verified import-MVA rung for the assessed scope.
An applicable duration from the evidenced stage to energisation, published by and matched to the observed site operator, rather than an offer-processing target.
Connection-dependent reinforcement scope and completion dates
Grid-works planning status and programme
Applicable connection-policy conditions and programme

Indicative HV and connection capex

Unknown

Rule and scope

Sum each published complete scope quantity multiplied by the matching published benchmark minimum and maximum. Configuration, voltage, route type, unit, country applicability, currency and explicit price base year must match. No assumed route length, transformer count, exchange rate, inflation, fee uplift or partial index is inserted. The result is an indicative benchmark band, not an operator quotation or contractual connection charge.

No observed inputs establish this result.

Published connection works scope

Unknown

Not established from the public records reviewed.

What complete connection scope is published: bays, stations, voltage, circuits, route lengths and underground or overhead configuration?

Scope completeness

Unknown

Not established from the public records reviewed.

Is the published connection scope complete enough to match every component to a sourced benchmark?

Scope questions

Obtain a published complete connection scope with voltage, configuration and measured quantities.
Establish that every necessary connection-work component is included in the published scope.
Identify network and customer works, upstream reinforcement, land and wayleaves, taxes, fees, securities, contingency and the price base.

Country reference bands and sources

No eligible published capex reference has been recorded. Country bands remain unknown.

Alternatives and policy exposure

Behind-the-meter generation

Unknown

Not established from the public records reviewed.

What behind-the-meter generation is evidenced, and at what scope?

Planning / policy requirement

Unknown

Not established from the public records reviewed.

Does the applicable planning or connection policy require behind-the-meter generation?

Battery storage

Unknown

Not established from the public records reviewed.

What battery storage is evidenced, and at what scope?

Planning / policy requirement

Unknown

Not established from the public records reviewed.

Does the applicable planning or connection policy require battery storage?

Private wire

Unknown

Not established from the public records reviewed.

What a private wire is evidenced, and at what scope?

Planning / policy requirement

Unknown

Not established from the public records reviewed.

Does the applicable planning or connection policy require a private wire?

Gas

Unknown

Not established from the public records reviewed.

What gas supply or generation is evidenced, and at what scope?

Planning / policy requirement

Unknown

Not established from the public records reviewed.

Does the applicable planning or connection policy require gas supply or generation?

Connection claim against current policy

Unknown

Not established from the public records reviewed.

Does the published connection claim meet the policy applicable to its application date, location and agreement status?

Open questions for a Reality Check

Generated from unknown fields, missing derivation inputs and unresolved evidence. The questions identify the documents or specialist checks needed next.

60 questions to resolve

Which TSO or DSO is responsible for this demand connection?
Not established from the public records reviewed.
What is the operator-confirmed connection substation or circuit?
Not established from the public records reviewed.
What voltage level is specified for the demand connection?
Not established from the public records reviewed.
What are the evidenced site and connection-point coordinates, and their calculated straight-line distance?
Not established from the public records reviewed.
What grid route length is published, and for which circuit?
Not established from the public records reviewed.
What applied mva is evidenced for the assessed site scope?
Not established from the public records reviewed.
What is the effective date of the applied connection evidence?
Not established from the public records reviewed.
Which buildings or phases does the applied connection evidence cover?
Not established from the public records reviewed.
What evidence level can be supported for capacityLadder.applied?
Verification has not been established.
What offered mva is evidenced for the assessed site scope?
Not established from the public records reviewed.
What is the effective date of the offered connection evidence?
Not established from the public records reviewed.
Which buildings or phases does the offered connection evidence cover?
Not established from the public records reviewed.
What evidence level can be supported for capacityLadder.offered?
Verification has not been established.
What accepted or contracted mva is evidenced for the assessed site scope?
Not established from the public records reviewed.
What is the effective date of the accepted connection evidence?
Not established from the public records reviewed.
Which buildings or phases does the accepted connection evidence cover?
Not established from the public records reviewed.
What evidence level can be supported for capacityLadder.accepted?
Verification has not been established.
What energised mva is evidenced for the assessed site scope?
Not established from the public records reviewed.
What is the effective date of the energised connection evidence?
Not established from the public records reviewed.
Which buildings or phases does the energised connection evidence cover?
Not established from the public records reviewed.
What evidence level can be supported for capacityLadder.energised?
Verification has not been established.
What connection agreement type and current status are documented?
Not established from the public records reviewed.
Does the agreement impose phased import-capacity limits?
Not established from the public records reviewed.
What flexibility or curtailment obligations apply?
Not established from the public records reviewed.
What on-site generation obligations apply?
Not established from the public records reviewed.
What securities are required, posted and still valid?
Not established from the public records reviewed.
What connection longstop or milestone dates apply?
Not established from the public records reviewed.
What is the published IT load in MW?
Not established from the public records reviewed.
On what electrical basis is the IT load in MW stated?
Not established from the public records reviewed.
Which phase or campus does the IT load in MW cover?
Not established from the public records reviewed.
What is the published facility load in MW?
Not established from the public records reviewed.
On what electrical basis is the facility load in MW stated?
Not established from the public records reviewed.
Which phase or campus does the facility load in MW cover?
Not established from the public records reviewed.
What is the published import capacity in MVA?
Not established from the public records reviewed.
On what electrical basis is the import capacity in MVA stated?
Not established from the public records reviewed.
Which phase or campus does the import capacity in MVA cover?
Not established from the public records reviewed.
What operator-published connection-to-energisation duration applies to this site and connection stage?
An application-to-offer processing target is not an energisation duration.
Which reinforcements does the connection depend on, and what dates are published?
Not established from the public records reviewed.
Which grid works require planning, and what is their current consent status and dated programme?
Not established from the public records reviewed.
Which connection-policy conditions apply, and when could they be satisfied?
Not established from the public records reviewed.
What complete connection scope is published: bays, stations, voltage, circuits, route lengths and underground or overhead configuration?
Not established from the public records reviewed.
Is the published connection scope complete enough to match every component to a sourced benchmark?
Not established from the public records reviewed.
What behind-the-meter generation is evidenced, and at what scope?
Not established from the public records reviewed.
Does the applicable planning or connection policy require behind-the-meter generation?
Not established from the public records reviewed.
What battery storage is evidenced, and at what scope?
Not established from the public records reviewed.
Does the applicable planning or connection policy require battery storage?
Not established from the public records reviewed.
What a private wire is evidenced, and at what scope?
Not established from the public records reviewed.
Does the applicable planning or connection policy require a private wire?
Not established from the public records reviewed.
What gas supply or generation is evidenced, and at what scope?
Not established from the public records reviewed.
Does the applicable planning or connection policy require gas supply or generation?
Not established from the public records reviewed.
Does the published connection claim meet the policy applicable to its application date, location and agreement status?
Not established from the public records reviewed.
Which checked country-grid sources and location-specific constraints apply to this connection?
No country-context relationship has been established for this record.
Identify network and customer works, upstream reinforcement, land and wayleaves, taxes, fees, securities, contingency and the price base.
Connection-cost scope question.
Resolve the energisation input: A dated, document-verified import-MVA rung for the assessed scope.
This missing input leaves an energisation bound unknown.
Resolve the energisation input: An applicable duration from the evidenced stage to energisation, published by and matched to the observed site operator, rather than an offer-processing target.
This missing input leaves an energisation bound unknown.
Resolve the energisation input: Connection-dependent reinforcement scope and completion dates
This missing input leaves an energisation bound unknown.
Resolve the energisation input: Grid-works planning status and programme
This missing input leaves an energisation bound unknown.
Resolve the energisation input: Applicable connection-policy conditions and programme
This missing input leaves an energisation bound unknown.
Obtain a published complete connection scope with voltage, configuration and measured quantities.
This scope or reference gap prevents a complete indicative connection capex band.
Establish that every necessary connection-work component is included in the published scope.
This scope or reference gap prevents a complete indicative connection capex band.

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Earlier capacity notes and source context

16.8 MW unspecifiedPhase-one contractor scope

Sweet Projects' phase-one case-study rating; MW basis is unspecified and not treated as IT power or utility import.

Published claimCapacity source

54 MW unspecifiedTwo-centre consultant design scope

Stantec describes compute capacity across two centres; exact rating basis, current commissioned extent and utility import remain unverified.

Published claimCapacity source

IT load, facility demand, import capacity and equipment ratings retain their stated scope. A published figure does not establish spare or transferable supply.

Planning & utilities

7 of 10 categories contain evidence. Each status applies to its specific claim.

Planning & decisions

Partial evidence

Runnymede's 2021 Longcross SLAA appendix links the wider Garden Village allocation to Policy SD9 and permission RU.13/0856, including 36,000 m² of sui-generis data-centre use. A July 2023 sequential test submitted by another applicant describes Longcross's RU.21/0780 reserved matters as approved/under construction. This is corroborating planning history, not the actual Ark decision notice or authority for all later expansion.

Sources & next check

Evidence reviewed 27 Sept 2026

Next check

Retrieve RU.13/0856 and RU.21/0780 signed decisions, approved Ark red lines and discharge records; check subsequent variations and distinguish the data-centre parcel from the wider Garden Village.

Runnymede: 2021 SLAA Longcross appendix and Policy SD9 development scopeSource: Publication date unstated
Be First: July 2023 sequential test filed with Runnymede, Longcross comparator and RU.21/0780Source: Publication date unstated

Land-use zoning

Partial evidence

The council's SLAA appendix identifies Policy SD9's wider Longcross Garden Village allocation, including a specific data-centre-use component. The whole allocation's mixed-use scope and area must not be applied to the Ark parcel or treated as current unrestricted development capacity.

Sources & next check

Evidence reviewed 27 Sept 2026

Next check

Match the Ark title/approved boundary to the adopted allocation map and specific data-centre permission; verify later policy changes and residual development limits.

Runnymede: 2021 SLAA Longcross appendix and Policy SD9 development scopeSource: Publication date unstated

Land, footprint & access

Partial evidence

The July 2023 sequential test treats the wider 17.7 ha Longcross Park comparator as sold to Ark, committed and unavailable for that applicant's alternatives assessment. This is not verified title or Ark's exact parcel area. Sweet Projects describes restricted phase-one logistics, off-site staff parking and road/service works. The operating development is not an off-market available land opportunity.

Sources & next check

Evidence reviewed 27 Sept 2026

Next check

Verify title and the precise Ark parcel, legal access and shared roads, service corridors and expansion rights; confirm construction logistics restrictions for subsequent phases.

Be First: July 2023 sequential test filed with Runnymede, Longcross comparator and RU.21/0780Source: Publication date unstated
Sweet Projects: Longcross phase-one principal contractor and scopeSource: Publication date unstated

Flood, ground & environment

Partial evidence

The 2023 submitted sequential test records no Flood Zone 2/3 coverage for the wider Longcross Park comparator. Sweet Projects identifies noise-sensitive residential/commercial neighbours and constrained logistics. Neither source establishes building-level surface-water safety, contamination clearance or current acoustic compliance.

Sources & next check

Evidence reviewed 27 Sept 2026

Next check

Obtain Ark-specific approved flood/drainage, ground investigation and remediation records; verify current noise limits, monitoring and mitigation against the occupied and proposed phases.

Be First: July 2023 sequential test filed with Runnymede, Longcross comparator and RU.21/0780Source: Publication date unstated
Sweet Projects: Longcross phase-one principal contractor and scopeSource: Publication date unstated

Water, cooling & heat

Documented

Ark's February 2026 update describes the commissioned Nebius Blackwell deployment using an air-cooled configuration. Stantec's wider Longcross design account describes BladeRoom direct-air technology and broader air/liquid capability; that does not change the configuration of the named deployed customer or prove liquid cooling in every hall.

Sources & next check

Evidence reviewed 27 Sept 2026

Next check

Confirm cooling as-builts by phase and customer, peak water demand/discharge arrangements and any heat-reuse contract; retain the distinction between commissioned air cooling and wider design capability.

Ark: commissioned Nebius deployment and air-cooled configurationSource: 16 Feb 2026
Stantec: Longcross design and construction support, team and campus scopeSource: Publication date unstated

Demand & location fit

Documented

Ark identifies delivery and commissioning of Nebius AI infrastructure at Longcross in February 2026. Nebius' June 2025 digest, published 8 July 2025, identifies its UK cloud deployment at Longcross for enterprise, research and public-sector uses. These are named customer/location evidence, but neither establishes occupied/contracted MW or spare capacity.

Sources & next check

Evidence reviewed 27 Sept 2026

Next check

Obtain a phase-specific customer capacity or occupancy disclosure and confirm the current service envelope without inferring MW from the presence of a cloud customer.

Ark: commissioned Nebius deployment and air-cooled configurationSource: 16 Feb 2026
Nebius: June 2025 digest identifies Longcross UK cloud deploymentSource: 8 Jul 2025

Programme & delivery

Documented

Sweet Projects identifies itself as phase-one principal contractor for enabling, Stage 4/5 design, construction and associated energy-centre/services/road works, describing 2023–2025, 90 weeks and 16.8 MW with no clear rating basis. Stantec describes a two-centre 54 MW compute-capacity design scope and names Sweet and Hale Architects. These are different scopes; neither proves 54 MW commissioned or a utility import entitlement.

Sources & next check

Evidence reviewed 27 Sept 2026

Next check

Reconcile building IDs, as-built capacity basis and commissioning dates across Sweet's phase one and Stantec's two-centre scope; verify Hale's exact phase appointment and current import separately.

Sweet Projects: Longcross phase-one principal contractor and scopeSource: Publication date unstated
Stantec: Longcross design and construction support, team and campus scopeSource: Publication date unstated
Ark: commissioned Nebius deployment and air-cooled configurationSource: 16 Feb 2026

Not assessed

Grid & import rightsFibre & dark fibreOwnership & development control

Evidence still needed

Grid & import rights
Site-specific import rights, available MVA, connection milestones and any transfer restrictions remain unverified.
Fibre & dark fibre
No verified site entry, dark-fibre offer or physically diverse route assessment is recorded. Regional coverage alone is insufficient.
Ownership & development control
Legal title, land-owning entity, development-control route and restrictions need verification. A named developer does not establish availability.

Project team

Appointments are limited to the project, phase and scope supported by each source.

Main contractor

Sweet ProjectsOther projects

Longcross phase-one principal contractor: enabling, Stage 4/5 design, construction, energy centre, ancillary services, gantry and roads; case study gives 2023–2025 and 90 weeks.

Appointment source

Architect

Hale ArchitectsOther projects

Architect named in Stantec's Longcross project team; exact building/phase appointment has not been separately established.

Appointment source

Engineering consultant

StantecOther projects

Multidisciplinary design and construction support, including substructure optimisation and EV infrastructure; consultant page describes a two-centre design scope.

Appointment source

Unlisted roles have no project-specific appointment recorded.

Sources

Publication dates are shown where known. Review dates do not establish approval or commissioning.

Original documents and maps retain their rights. Public access does not grant commercial redistribution rights.