R (on the application of Bronwen Manby) v Mayor and Burgesses of the London Borough of Hackney [2026] EWHC 1543 (Admin)
Manby v Hackney is a Planning Court judgment about material considerations, supplementary planning guidance and the reasoning required when a planning officer relies on a design rule. Hackney granted permission for extensions to a house, but the High Court quashed that permission because the council recognised its 45-degree rule as relevant without actually assessing what the rule meant for the neighbouring property.
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- Neutral citation
- [2026] EWHC 1543 (Admin)
- Court
- High Court of Justice, King's Bench Division, Planning Court
- Judgment date
- 2nd July 2026
- Judge
- HHJ Russen KC (sitting as a judge of the High Court)
- Case number
- AC-2025-LON-003605
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What Manby v Hackney decided
The case concerned planning permission for lower ground floor and upper ground floor rear extensions, together with a mansard roof extension, at 87 Culford Road in Hackney. The neighbour at No. 89 objected, including on the basis that the proposal did not respect Hackney’s 45-degree rule.
Hackney’s officer report quoted the 45-degree rule and recognised it as a guide relevant to residential amenity. However, the officer did not determine whether the rule was met in relation to No. 89 and did not establish the centre point of the relevant neighbouring window needed to apply it.
HHJ Russen KC held that the permission was unlawful and should be quashed. The council had recognised the 45-degree rule as a material consideration but had not assessed its potential impact on the decision.
The 45-degree rule was guidance, not an automatic refusal
The judgment is important because it does not say that failing a 45-degree rule automatically means planning permission must be refused.
The rule appeared in a Supplementary Planning Document rather than the statutory development plan. The court expressly accepted that the SPD did not create a presumption against granting permission where the rule was not met. It remained guidance requiring the exercise of planning judgment.
The legal problem was different. Once Hackney treated the 45-degree rule as a material consideration and the neighbour had raised it directly, the council could not simply note that the rule existed and then move on. It had to consider what weight, if any, the rule carried in the circumstances of the application.
Having regard to a material consideration means more than mentioning it
Section 70(2) of the Town and Country Planning Act 1990 requires a local planning authority to have regard to material considerations when dealing with a planning application. The court said that this involves more than paying lip service to a consideration.
Merely recording that a matter exists, without some assessment of how it bears upon the decision, is not a proper exercise of having regard to it. In this case the officer report identified the 45-degree rule but did not apply it to No. 89 or explain its significance.
Officer reports, process irrationality and the Tameside duty
The court also found that the same failure amounted to process irrationality and a breach of the Tameside duty to take reasonable steps to obtain the information needed for a rational decision.
The officer report concluded that the extensions would not cause an unacceptable impact on neighbouring amenity, but there was a critical gap between recognising the 45-degree rule and reaching that conclusion. The court said the rule had effectively been left in the toolbox rather than used to test the proposal.
The reasoning was also inadequate. A reader could not understand how the neighbour’s 45-degree-rule objection had been resolved, leaving genuine rather than merely forensic doubt about what had been decided and why.
Why the permission was quashed
Hackney argued that permission would highly likely have been granted even if there had been an error. The court was not persuaded that the high threshold in section 31(2A) of the Senior Courts Act 1981 was met.
The judge declined to substitute the court’s own planning judgment for that of the council. The planning permission was therefore quashed.
What Manby does not mean
- a breach of a local 45-degree guide does not automatically require refusal
- an SPD does not acquire the status of the development plan simply because it contains precise guidance
- the court was not deciding whether the extension was acceptable on its planning merits
- the problem was the failure to assess a material consideration that the council itself had identified as relevant
Read the full Manby v Hackney judgment
The approved judgment is held in the Planning Geek case law library. Gold Members can open the protected PDF below. If you are not signed in with Gold access, the button will take you to the appropriate membership option.
Related Planning Geek guidance
For the practical design issue, see our guide to the 45-degree rule for extensions. We also explain the role of Supplementary Plans and SPDs and how to read planning officer reports. If you are considering a householder scheme, see the pages on rear extensions and the larger home extension.
Manby v Hackney Case Law Page Updated: 9th September 2026