Supreme Court of the United Kingdom · Unanimous; single judgment of Lord Reed, with whom Lord Hodge, Lord Lloyd-Jones, Lord Sales and Lord Stephens agreed
Facts
The Scottish Parliament passed the UNCRC (Incorporation) (Scotland) Bill and the European Charter of Local Self-Government (Incorporation) (Scotland) Bill. The UNCRC Bill required legislation, including Acts of the UK Parliament so far as they applied in devolved areas, to be read compatibly with the Convention rights it defined, and empowered courts to make strike-down declarators and incompatibility declarators in respect of legislation. It also made it unlawful for public authorities to act incompatibly with those rights. The Charter Bill made similar provision in respect of local government. The Attorney General and the Advocate General referred specified provisions under s.33 of the Scotland Act 1998.
Issue
Whether the referred provisions of the two Bills were outside the legislative competence of the Scottish Parliament because they would modify s.28(7) of the Scotland Act 1998, which is protected from modification by Schedule 4.
Held
The referred provisions of both Bills were outside the legislative competence of the Scottish Parliament so far as they applied to Acts of the UK Parliament, including the interpretation obligation, the strike-down and incompatibility declarator provisions, and the extension of the public authority duty to acts required by UK legislation.
Ratio
- A provision of an Act of the Scottish Parliament modifies s.28(7) of the Scotland Act 1998 if it limits or qualifies the power of the UK Parliament to make laws for Scotland, and that includes a provision which subjects Westminster legislation to judicial review or reinterpretation by reference to standards set by the Scottish Parliament, or which conditions its practical effect, even if it does not purport to bind Parliament as a matter of law.
The judgments
Lord Reed (lead)
Held that s.28(7) reflects the continuing sovereignty of the UK Parliament, a fundamental principle of the UK constitution which devolution did not alter. A modification of s.28(7) is not confined to an express restriction on Westminster; provisions that would make the validity or effect of UK Acts depend on Scottish legislation, or that would deter or condition Westminster's exercise of its power, modify it. Provisions requiring Scottish courts to read UK Acts compatibly with the Bill's rights, or to declare them invalid or incompatible, therefore fell outside competence.
Key reasoning
- The Scottish Parliament is a creation of statute with limited powers, and s.28(7) and Schedule 4 protect the UK Parliament's unqualified power to legislate for Scotland from modification by it.
- Whether a provision modifies s.28(7) depends on its legal and practical effect, not merely its form; a provision can modify the power by attaching consequences to its exercise.
- Requiring Scottish courts to read Acts of the UK Parliament compatibly with rights defined by the Scottish Parliament, and to strike them down or declare them incompatible, would subject Westminster legislation to a form of control by the devolved legislature.
Where it fits in the module
In the devolution materials the case shows parliamentary sovereignty operating as a structural rule of the devolution statutes rather than merely an abstract doctrine, through s.28(7) and Schedule 4 of the Scotland Act 1998. It parallels the position in Wales, where Westminster's continuing power to legislate is similarly preserved by the Government of Wales Act 2006. It also prompts debate about whether the Sewel convention and the political reality of devolution sit uneasily with so strong a legal account of Westminster supremacy.
Criticisms
- Reading modification of s.28(7) to include practical or chilling effects, not just legal limits, gives the provision a breadth that could constrain the Scottish Parliament's ability to legislate in devolved areas where UK Acts apply.
- The reasoning arguably treats devolution as a delegation from a sovereign centre, discounting the constitutional significance and democratic legitimacy of the devolved legislatures.
- Since Westminster could in any event legislate contrary to the Bill, it can be argued that the provisions posed no real threat to sovereignty and could have been read down rather than held outside competence.
Written with AI (claude-opus-5.5 (Claude Code writer)) on 1 November 2026, reviewed for errors by a second model (claude-sonnet-5.5 (Claude Code checker)). Read the case itself at [2021] UKSC 42. Spotted an error? Tell us.