High Court Finds Material Error of Fact in Planning Decision Regarding Trees: Analysis of Dr. Caroline Rye v Secretary of State Case

Citation: [2024] EWHC 358 (Admin)
Judgment on


The High Court judgment in the case of Dr. Caroline Rye v Secretary of State for Levelling Up, Housing and Communities & Ors concerns a claim for statutory review under section 288 of the Town and Country Planning Act 1990 regarding the granting of planning permission by a Planning Inspector following a successful planning appeal. This article analyzes the judgment, focusing on the key legal principles applied in the case and linking them directly to relevant portions of the summary.

Key Facts

The crux of the case was the claimant’s contention that the Planning Inspector made a material error of fact regarding the trees on the site subject to the planning appeal. Specifically, trees depicted as retained in the appeal proposal had been felled, a fact the Inspector seemingly overlooked in her analysis. The felling of these trees was argued to be a significant factor affecting the development’s character and appearance, particularly in relation to the Conservation Area.

Several key legal principles formed the basis of the court’s reasoning:

  1. Flexibility in Decision Letters: Following the approach of Bloor Homes East Midlands Ltd. v. Secretary of State for Communities and Local Government [2014] EWHC 754 (Admin), the court held that decision letters by Inspectors need not rehearse every aspect of the evidence or address every argument, given they’re primarily for parties knowledgeable about the issues and evidence in the dispute.

  2. Reference to Material Considerations: In line with Bolton MDC v. Secretary of State for the Environment (1996) 71 P&CR 309, the court noted that an Inspector isn’t obliged to refer to all evidence or every material consideration.

  3. Test for Material Error of Fact: The court applied the four criteria from E v Secretary of State for the Home Department [2004] EWCA Civ 49, which determine when an error of fact can render a decision unlawful.

  4. Application of Simplex Case and Section 31(3D) Senior Courts Act 1981: From Simplex (GE) Holdings v. Secretary of State for the Environment [1998] 3 PLR 25, the court recognized that an error does not necessarily vitiate a decision if the decision would have been the same without it. However, the court must be confident that the outcome would not have been substantially different for this principle to apply.


The judgment found that the Inspector made a material error of fact concerning the trees supposed to be retained. This mistake met all four E criteria: it concerned an existing fact, the fact was uncontentious and objectively verifiable, the claimant was not responsible for the error, and the mistake played a material part in the Inspector’s decision.

The court strongly considered the Inspector’s misunderstanding and observed that it influenced her assessment of the impact on the character and appearance of the area. The imposition of a condition to protect trees that were no longer present was both unenforceable and imprecise.

Finally, the court refuted the submission that the Inspector found the remaining trees an acceptable backdrop, as the Inspector’s site visit occurred six months after the felling and the outcome of the decision without the material mistake was not determinable.


The High Court’s analysis in Dr. Caroline Rye v Secretary of State for Levelling Up, Housing and Communities & Ors demonstrates the delicate interplay between the understanding of material facts and legal principles guiding planning decisions. The judgment highlights the crucial role that accurate fact-finding plays in underpinning lawful decision-making within the planning context. It underscores the importance of decision letters reflecting current and accurate information about the circumstances relevant to planning determinations. The case was ultimately decided on the basis that a material error of fact concerning retained trees influenced the Inspector’s analysis, mandating the quashing of the Inspector’s decision.