General
This section is one of a number dealing with the legislative competence of the Parliament.
The limits upon the legislative competence of the Scottish Parliament are set out in sections 28-30, together with the list of reserved matters in Schedule 5 and the entrenched enactments and rules of law in Schedule 4. Any provision in an Act of the Scottish Parliament which falls outside those limits is ultra vires and void, subject to any order made by the courts under section 102. There are various provisions providing for a Bill to be scrutinised before it is enacted to ensure that it is intra vires, both before its introduction (section 31) and by the Judicial Committee after it has been passed but before it is submitted for Royal Assent (sections 32- 34). After the Bill has been enacted, any question as to whether the Act or some provision in it is outside the legislative competence of the Parliament is a devolution issue and attracts the special procedures in Schedule 6
However, there are certain limited circumstances where the UK Government can exercise a policy control or veto over what legislation is enacted by the Scottish Parliament, even although it is within its competence. This section defines what those circumstances are. There is a related power in section 58(4) enabling the Secretary of State, in similar circumstances, to revoke subordinate legislation made by a member of the Scottish Executive.