Percy v Hall

A byelaw is not void for uncertainty merely because its language or application may be difficult at the margins. The applicable test is whether the byelaw has a sensible and ascertainable meaning and is capable of certain application in some circumstances. Where a person may reasonably be in doubt whether conduct falls within a penal byelaw, the doubt must be resolved so as to avoid conviction.

A byelaw designating land need identify the protected area with certainty. It need not describe its boundary separately where the area itself is sufficiently identified. A constable acting on apparently valid byelaws may have lawful justification for an arrest if the constable reasonably believed that an offence was being committed, even if the byelaws are later held invalid.

The respondents had repeatedly been arrested and removed from the vicinity of Menwith Hill Station for alleged breaches of the HMS Forest Moor and Menwith Hill Station Byelaws 1986. They brought civil claims for wrongful arrest and false imprisonment against Ministry of Defence police officers and others.

Sir Peter Webster, sitting as a Deputy High Court judge, held that the byelaws were invalid for uncertainty, following Bugg v DPP [1993] QB 473, but held that invalidity would not necessarily deprive the constables of lawful justification. Both sides challenged aspects of those rulings. The central issues were the certainty of the protected area and the effect of any invalidity upon the arrests.

1. Appeal allowed unanimously. Lord Justice Simon Brown gave the principal judgment. Lord Justice Peter Gibson agreed with it and added reasons. Lord Justice Schiemann agreed with both judgments.
2. The byelaws were valid. The expression identifying land belonging to the Secretary of State in specified parishes, read with the annexed plan, identified the protected area with sufficient certainty. The fact that a person on the ground might need further inquiry to establish ownership of a particular part did not make the byelaws void. The plan could assist identification, although it could not override the verbal description.
3. The court respectfully disagreed with the relevant conclusion in Bugg v DPP [1993] QB 473. Section 2(5) of the Military Lands Act 1900 expressly required boundary descriptions for particular tidal or coastal areas. It did not support an implied general requirement that every byelaw made under section 14 of the Military Lands Act 1892 must describe its boundaries. The validity of the instrument was determined when it was made and could not depend upon later boundary marking required by section 17(1).
4. The court preferred the approach in Fawcett Properties Ltd v Buckingham County Council [1964] AC 636 to the adequate-information formulation derived from Kruse v Johnson [1898] 2 QB 91. A byelaw should be upheld unless it has no sensible or ascertainable meaning, or is incapable of certain application in any case. Criminal consequences require ambiguity to be resolved, where reasonably possible, in favour of avoiding a penalty; they do not require invalidation of a byelaw that plainly governs at least some conduct.
5. Although unnecessary to the result, the court also held that later invalidity would not automatically make the constables’ earlier arrests tortious. Applying the reasoning in Wills v Bowley [1983] AC 57, a constable could be justified where acting on a reasonable belief that a byelaw offence was being committed. The general retrospective effect of invalidity did not convert conduct which was, at the time, the reasonable enforcement of apparently valid legislation into actionable wrongdoing. The court proposed that this conclusion be reflected in a declaratory judgment.

• Court of Appeal (Civil Division) — Allowed the defendants’ appeal and held the byelaws valid. It also expressed the proposed declaratory conclusion on lawful justification.
• High Court — Sir Peter Webster, sitting as a Deputy High Court judge, held the byelaws invalid for uncertainty but held that invalidity would not necessarily deprive the constables of lawful justification.