The United Nations Convention on the Rights of the Child (Incorporation) (Scotland) Bill (UNCRC) and the European Charter of Local Self-Government (Incorporation) (Scotland) Bill (ECLSG) have been sent back to Holyrood to receive further consideration.

The president of the court, Lord Reed, gave the sole judgment, with which Lord Hodge, Lord Lloyd-Jones, Lord Sales and Lord Stephens agreed.

Sir James Eadie QC, David Johnston QC, Christopher Pirie and Christopher Knight appeared for the Attorney General and Advocate General for Scotland and were instructed by the Office of the Advocate General for Scotland. James Mure QC, Paul Reid and Lesley Irvine, instructed by the Scottish Government Legal Directorate, appeared for the Lord Advocate.

The bills aim to give effect to the respective instruments of their titles. The law officers’ references “reflect concerns that some of the provisions of the bills would impinge on matters which lie outside the legislative competence of the Scottish Parliament”, Lord Reed said.

He added: “The Scottish Parliament is a democratically elected legislature with a mandate to make laws for Scotland. It has plenary powers within the limits of its legislative competence. But it does not enjoy the sovereignty of the Crown in Parliament: rules delimiting its legislative competence are found in section 29 of and Schedules 4 and 5 to the Scotland Act, to which the courts must give effect.

“And Parliament also has an unlimited power to make laws for Scotland, a power which the legislation of the Scottish Parliament cannot affect: section 28(7) of the Scotland Act. The Scotland Act must be interpreted in the same way as any other statute.”

The court found that three provisions of the UNCRC Bill would modify section 28(7) of the Scotland Act and, for that reason, would fall outside the legislative competence of the Scottish Parliament.

The first is section 19(2)(a)(ii); the second s.20(10)(a)(ii) and the third s.21(5)(b)(ii). The first attempts to qualify the power of the Westminster Parliament; the second would allow the courts to strike down acts of Parliament incompatible with the UNCRC under certain circumstances and the third would let the courts declare acts of Parliament to be incompatible with the UNCRC under certain circumstances.

It was agreed that another provision of the same bill was, on its face, ultra vires but, argued counsel for the Lord Advocate, it was, nonetheless permissible because the courts would be able to interpret it so as to impose corrective limitations in individual cases. Again, however, this would be outside the legislative competence of Holyrood because it would circumvent the system of pre-enactment scrutiny.

Finally, the court decided that two provisions of the ECLSG Bill would modify section 28(7) of the Scotland Act and, for that reason, fall outside the competence of the Scottish Parliament. The first is section 4(1A) of the ECLSG Bill, which provides that acts of the UK Parliament “must be read and given effect in a way which is compatible with” the ECLSG. This would sometimes require the courts to modify the meaning and effect of Acts of Parliament, producing results which the UK Parliament did not intend. Accordingly, for the same reasons as section 19(2)(a)(ii) of the UNCRC Bill, section 4(1A) of the ECLSG Bill would be outside the legislative competence of the Scottish Parliament.

The second provision of the ECLSG Bill is section 5(1), which would confer on the courts the power to declare that an act of the UK Parliament is incompatible with the ECLSG. For the same reasons as section 21(5)(b)(ii) of the UNCRC Bill, section 5(1) of the ECLSG Bill would affect the power of the UK Parliament to legislate for Scotland.

It would therefore be outside the legislative competence of the Scottish Parliament.