Summary
- Hertsmere Borough Council deferred Ark's planning application on 5 November rather than granting or refusing permission.
- Outstanding issues include water supply evidence, building design, and potential Section 106 contributions.
- Ark proposes a campus associated with 250MVA of electrical capacity from 2028, but the development remains subject to planning consent.
Hertsmere Borough Council has deferred a decision on Ark Data Centres’ proposed £2.5bn campus near Watford, requesting further information about water supply, building design, and developer contributions before determining the application.
The council’s Planning Committee considered the Hilfield Park development on 5 November but agreed to postpone its decision. The proposal has neither been approved nor refused, despite officers having recommended that planning permission be granted.
Ark Data Centres wants to redevelop the former Mercure Hotel site at Tylers Way into a substantial data centre campus serving the London market.
The application, registered under reference 25/1781/FUL, includes computing buildings, electricity infrastructure, water infrastructure, internal roads, security arrangements, landscaping, and associated development works.
Ark has associated the project with more than £2.5bn of private investment. Its published development information describes approximately 250MVA of electrical capacity to be delivered across multiple buildings from 2028.
The 250MVA figure represents a proposed electrical capacity specification. It should not be interpreted as commissioned IT load or as evidence that the project has secured every approval and infrastructure connection required for operation.
Councillors raised concerns about whether adequate water supply would be available for the development and requested further evidence from Affinity Water before reaching a decision.
Local Democracy Reporting Service coverage of the meeting described members seeking written confirmation of the supply arrangements. Questions about water requirements were among the issues that prevented the committee from accepting the officer recommendation immediately.
Data centre water demand depends on cooling design, equipment configuration, operating conditions, and the supporting building systems. A development’s projected consumption must therefore be assessed against the particular technical arrangements proposed rather than a generic estimate for facilities of similar size.
For the Hertsmere application, the planning committee wants further evidence about the capacity of the local water infrastructure to accommodate the scheme.
Design and developer contributions under scrutiny
The committee also examined the scale and visual effect of the proposed buildings, including their relationship with neighbouring properties and sensitive locations.
Concerns raised during consideration of the application included the development’s height and its potential effect on views from nearby land. The site is within the Metropolitan Green Belt, placing additional weight on the planning assessment of its location and physical impact.
The planning framework requires the authority to consider the development against applicable national and local policies, the submitted technical evidence, and representations received during consultation.
Officers had recommended approval, but their assessment did not bind committee members. Councillors were entitled to request further information where they considered that relevant planning matters remained unresolved.
Financial contributions also featured prominently in the debate. Councillor Christian Gray suggested seeking approximately £2m from the developer towards training, employment initiatives, and local economic development.
That figure remains a proposal raised during the committee meeting, not an agreed payment or binding planning obligation.
Section 106 agreements can secure contributions or measures connected with a development where the relevant legal and planning tests are satisfied. Any final arrangement would need to be justified by the project’s effects and properly documented.
The committee’s decision therefore leaves several matters for further discussion between Ark, council officers, and the relevant infrastructure providers.
The developer may submit additional technical information, clarify existing evidence, or consider design and planning-obligation changes before the application returns for determination.
Major data centre proposals increasingly involve substantial demands on electricity, water, transport, and other infrastructure. Those requirements can make a development more complex to assess than its building footprint alone would suggest.
In the case of Hilfield Park, the proposed investment and future computing capacity must be considered alongside the infrastructure needed to support the campus and the effects of building it at the selected location.
Hertsmere’s published committee schedule lists a further meeting on 26 November. That does not establish that the Ark application will be reconsidered on that date, and no confirmed return date has been identified.
Planning permission remains outstanding. The next stage will depend on whether the information requested by councillors is provided and whether the committee considers the resulting evidence sufficient to reach a decision.
