The Lord Advocate referred to the Supreme Court the question whether a Bill providing for a referendum on Scottish independence would be within the legislative competence of the Scottish Parliament. The Court held that it would not, because the Bill related to the reserved matters of the Union of Scotland and England and the sovereignty of the Parliament of the United Kingdom. A referendum, even though advisory, would have more than a loose connection with those matters.

The Northern Ireland Assembly elected a First Minister and Deputy First Minister after the six-week period in s.16(8) of the Northern Ireland Act 1998 had expired. A majority of the House of Lords held the election valid, because the Act did not require the Secretary of State to call a fresh Assembly election immediately and the Assembly retained power to elect late. The case is the classic statement that devolution statutes are constitutional in character and should be interpreted purposively to sustain the settlement.

The UK law officers referred provisions of two Scottish Parliament Bills, one incorporating the UN Convention on the Rights of the Child and one incorporating the European Charter of Local Self-Government, to the Supreme Court. The Court held that the provisions empowering Scottish courts to read down, strike down or declare incompatible Acts of the UK Parliament were outside competence, because they would modify s.28(7) of the Scotland Act 1998, which preserves Westminster's power to legislate for Scotland. The decision gives strong protection to parliamentary sovereignty within the devolution settlement.