In Short
The Situation: Since coming into power in July 2024, the UK government has made several planning policy decisions with the aim of facilitating data centre development.
The Development: On 9 July 2025, the Secretary of State granted planning permission on appeal for a 72,000-square-metre data centre in the Buckinghamshire Green Belt. Notable planning permissions for other data centres have also been granted in recent months by the Secretary of State and local authorities in England. These decisions show how the recent planning policy changes are assisting data centre developers in securing planning permissions.
Looking Ahead: Data centres are a sector that the UK government clearly wishes to promote and the trend in favour of large data centres looks set to continue.
Secretary of State Decision
Outline planning permission was sought for a data centre development at the Woodlands Park landfill site in Iver. The application had been refused by the local authority in June 2024. The Secretary of State utilised her power to "recover" the appeal—meaning she would take the ultimate decision rather than an inspector appointed on her behalf.
In granting the permission, the Secretary of State decided that there was a clear and undisputed need for new data centre capacity in the locality. Significant weight was also given to the economic benefits of the development and substantial weight was given to the employment benefits of the proposal.
Green Belt policies are generally intended to safeguard the Green Belt from development. However, the government has made changes to Green Belt policies in the National Planning Policy Framework ("NPPF") to make it easier to develop in the Green Belt in certain circumstances. The Secretary of State decided that the land on which the data centre would be located was "Grey Belt" land in accordance with the recently revised policies in the NPPF and that the data centre therefore was not inappropriate development in the Green Belt. She gave no weight to Green Belt harm in coming to her conclusion.
A Green Belt Hat-Trick for Data Centres
There have now been three recovered appeal decisions in seven months on large data centres in the Green Belt and on each occasion the Secretary of State has granted planning permission. Previous appeal decisions at Abbots Langley (May 2025) and Court Lane, Iver (December 2024), taken together with the latest decision, show an unmistakable interventionist trend in favour of economic growth.
Local Authority Decisions
On 12 February 2025, Hertsmere Borough Council granted outline planning permission for a 187,000 square-metre data centre on 34 hectares of Green Belt agricultural land in Hertfordshire.
In that case, the Council decided that the proposal was inappropriate development in the Green Belt and that it therefore had to meet the "very special circumstances" test for development in the Green Belt. However, the Council concluded this test was met due to the benefits of the scheme: meeting a proven need for data centres (given substantial weight); transport improvements (significant weight); and economic benefits including employment in the end use (substantial weight). These clearly outweighed the harm to the Green Belt and amounted to the very special circumstances required to justify the development.
On 8 May 2025, Northumberland County Council granted outline permission for a data centre scheme on the former power station site at Cambois. Each one of the 10 data centres would have a 72MW rating, with the buildings totalling up to 540,000 square metres, in addition to ancillary structures, substation, emergency generators and other associated works over 102 hectares.
The Cambois site is not in the Green Belt—a vacant brownfield site, allocated for employment use, it has been unused since 2003. It was attractive to data centre operators due to (among other reasons) its access to a power supply and the proximity to an existing National Grid substation. Planning permission had previously been granted for the development of a major battery manufacturing plant on the site.
In granting permission, the County Council gave significant weight to the fact that the UK government has classed data centres as Critical National Infrastructure and that the NPPF now expressly requires local authorities to make provision for data centres and grid connections.
What Lessons Can We Learn From These Decisions?
The Secretary of State's decision saw a number of policy changes coming together in favour of data centre development. As well as the classification of data centres as Critical National Infrastructure, the NPPF has been amended to expressly support data centre development. The changes the government has made to the NPPF Green Belt policies to introduce the "Grey Belt" concept also had a real impact in that decision, avoiding the need to show that very special circumstances existed to justify the development.
The local authority decisions show that the government's clear policy to encourage data centre development has been understood by local planning authorities. The Hertsmere decision is especially notable because a local authority found that the benefits of the scheme amounted to very special circumstances, and the authority decided to accept a data centre in the Green Belt rather than pushing the developer to an appeal to be decided by the Secretary of State.
They also show the need (as ever) for developers to address specific matters of local importance to secure consent. For the Hertsmere scheme, the developer agreed to pay £2 million towards improving local bus services through a section 106 planning agreement to gain their planning permission. At Cambois, operational shift working patterns at the data centres will be timed to avoid peak highway travel times, to address the requirements of the highway authority, and the section 106 obligations include an education, employment and training plan and a local supplier strategy.
Looking Ahead
The trend for permissions to be granted for large data centres looks set to continue given the clear government policy support. For example, North Lincolnshire Council is considering a planning application for a 1,000 MW AI data centre campus (905,000 square metres) on the site of the former RAF Elsham Wolds airfield (176 hectares). The application documents refer to it as "the largest data centre campus in the northern part of the UK, and indeed the whole of the UK at the time of preparing the planning application". Seven hectares of greenhouses would utilise the heat produced by the data centres. Although no decision has been taken yet on the application, the Council has expressed general support for this type of use in its district, so it seems likely that permission will be granted.
Two Key Takeaways
1. Government policy is expressly in favour of facilitating data centres and this has been recognised by local authorities.
2. Recent permissions granted for data centres confirm a definite trend which looks set to continue, with approvals anticipated for large-scale projects in the future.
