R v Secretary of State for the Home Department, ex parte Northumbria Police Authority [1989] QB 26

D put forward a circular which expressed that in the future, the Home Secretary is to undergo maintenance of a central store of plastic baton rounds and CS gas. The circular included a procedure enabling the local police to buy these. C, the Northumbria Police Authority, applied for judicial review against D and asserted that D did not possess the power under the royal prerogative to maintain peace to supply the above to the police in the absence of police authority. The Northumbria Police Authority argued the above using section 4(4) of the 1964 Act: “police authorities are to provide for the supply of equipment to their local forces.”

Whether the statutory equipment responsibilities of police authorities excluded the Home Secretary’s proposed central supply arrangements, or left room for statutory and prerogative authority.

The Court of Appeal dismissed the police authority's appeal and upheld the Home Secretary's arrangements. It rejected the argument that the statutory provisions conferred an exclusive local power which prevented the central supply proposed. The court also recognised a Crown prerogative relating to preservation of the peace as a basis relevant to the arrangements. The authority's responsibilities under the Police Act did not, on the court's interpretation, exclude the challenged action. This was not a ruling that ministers can disregard legislation whenever they invoke public safety. Its significance lies in the court's construction of the particular statutory allocation and its treatment of the prerogative alongside that allocation.

The statutory allocation of police-equipment responsibilities did not exclude the Home Secretary’s central supply arrangements. The Court of Appeal recognised a peacekeeping prerogative, but whether statute displaces prerogative depends on the scheme’s proper construction.

Northumbria Police Authority is a controversial illustration of the relationship between prerogative and statute. The court upheld central provision of riot-control equipment rather than treating local statutory equipment powers as exclusive. It should be compared carefully with De Keyser, where a statutory scheme displaced use of a corresponding prerogative. The outcome does not establish that prerogative always survives unless legislation expressly abolishes it. The question is whether the particular statutory scheme leaves room for the executive action, including its purpose and structure.