Blackburn v Attorney-General

Domestic courts do not adjudicate the merits or legal effect of an unimplemented treaty. Treaty-making is a prerogative of the Crown, exercised on ministerial advice, and its exercise cannot be challenged in the courts. Courts consider treaty obligations only after Parliament has implemented them, and then only to the extent Parliament directs. A court should not give general declarations about Parliament’s future legislative powers or decide in advance whether later legislation could undo treaty arrangements. Such questions must await a concrete dispute. The standing issue may remain undecided where the claim discloses no cause of action.

The appellant brought two actions against the Attorney-General, seeking declarations that the proposed accession to the Common Market and signature of the Treaty of Rome would permanently diminish parliamentary sovereignty and breach the law. The Attorney-General applied to strike out the statements of claim for disclosing no reasonable cause of action. The Master and Eveleigh J struck them out. The appellant appealed, raising the justiciability of the treaty-making power and whether implementing legislation could bind successor Parliaments.

Appeals dismissed with costs. The Court of Appeal was unanimous. The Master of the Rolls gave the principal reasons; Salmon LJ agreed, while Stamp LJ agreed in the result and expressed no view on the legal implications of accession to the Treaty of Rome.

1. Treaties and domestic law. The courts take no notice of treaties as such. Treaty obligations become relevant domestically only when embodied in legislation enacted by Parliament, and then only to the extent Parliament directs. The court assumed, without deciding, the appellant’s description of the legal effects of membership, including the material referred to in Costa v E.N.E.L. 1964 Common Market Law Reports, 425.
2. Treaty-making prerogative. The power to make treaties rests in the Crown, acting on the advice of Ministers. Even a treaty of major constitutional importance cannot be challenged or questioned in these courts. This principle was applied from Rustomjee v The Queen 1876 2 QBD 69.
3. Hypothetical future legislation. The court would not decide in advance whether Parliament could lawfully withdraw from treaty arrangements or whether implementing legislation could bind its successors. That question must be considered if and when the relevant legislation and circumstances arise. The distinction between abstract legal power and political reality, illustrated by Section 4 of the Statute of Westminster, 1931 and British Coal Corporation v The King P.C. 1935 AC 500 at p. 520, did not require a present determination.
4. Judicial function and standing. Salmon LJ emphasised that courts decide and enforce the law as it stands, rather than influence political decisions or determine what the law should become. Stamp LJ likewise rejected general declarations about Parliament’s powers where the proposed intervention was purely hypothetical. The court did not need to determine standing, dismissing both appeals because the statements of claim disclosed no cause of action.

1. Court of Appeal: In [1971] EWCA Civ 7, the appeals were dismissed with costs.
2. High Court: Mr Justice Eveleigh struck out the statements of claim on 27 February 1971 for disclosing no reasonable cause of action. The judgment appealed has no separate citation stated in the supplied text.