Manchester Ship Canal Company Ltd & Ors, R (on the application of) v Environment Agency

An administrative body must interpret its published policy according to its language, context and purpose. Where the policy creates formal and de facto flood-defence categories, a structure is formal only if flood defence is its primary function. A structure integral to infrastructure serving another primary purpose remains de facto where flood protection is a secondary or indirect consequence of normal operation. The decision-maker cannot avoid that distinction by inventing a third category based on two co-equal primary functions. The court defines the policy boundaries; the specialist agency applies them to the facts, subject to Wednesbury review. A classification based on a misconstruction of the policy, or outside the range of reasonable conclusions, is unlawful.

The Environment Agency designated sluices forming part of the Manchester Ship Canal as formal flood defences for flood-zone mapping purposes. The designation meant that the effect of the sluices was ignored when assessing flood risk, affecting proposed development on adjoining land.

The landowners sought judicial review. Mrs Justice Lang held that the Agency had misconstrued and irrationally applied its own policies, and quashed the decision: [2012] EWHC 1643 (QB). The Agency appealed, raising the question whether the sluices could properly be treated as formal flood defences where they were integral to the Canal’s navigation and water-level control functions.

Appeal dismissed. Moses LJ gave the judgment of the court, with which Rimer LJ and Gloster LJ agreed.

1. Interpretation and review. The court must interpret the Agency’s published distinction between formal and de facto defences objectively, by reference to the language used and the purpose of the distinction. Policy statements are not construed as statutory provisions. Once the categories are defined, whether a particular structure falls within one category or the other is an expert judgment for the Agency, subject to challenge on Wednesbury grounds. The court applied the approach in Tesco Stores Limited v Dundee City Council [2012] UKSC 13.
2. Scope of the policy. The Agency’s policies confined formal flood defences to structures whose primary function was flood defence. Structures whose primary function was normal infrastructure operation, but which also provided flood protection, were de facto defences. The policies recognised only two categories. The Agency could not avoid that distinction by describing the sluices as having two co-equal primary purposes or by creating a third category in practice. A departure from published policy would have required express notice and an opportunity for affected parties to make representations.
3. Application to the sluices. The sluices were integral to the Canal and operated principally to maintain water levels for navigation. Their reduction of flood risk resulted from that normal operation. The fact that they controlled flood flows and prevented overtopping did not make them formal flood defences. The statutory obligations in sections 71(13), 84(5), 84(16), 101(6), 114(1) and 118(2) of the Manchester Ship Canal Act 1885, including the description of certain structures as lock and flood gates, did not justify widening the Agency’s policy categories.
4. The Agency’s classification was therefore a misunderstanding of its own policy and was outside the range of reasonable conclusions. The alternative ground relied upon by the respondents did not arise.

• Court of Appeal (Civil Division): The Environment Agency’s appeal was dismissed: [2013] EWCA Civ 542.
• Administrative Court, Queen’s Bench Division: Lang J allowed the judicial review challenge and held that the sluices were not formal flood defences under the Agency’s policies: [2012] EWHC 1643 (QB).