Extent of legislative authority of Parliament

11.8Primary legislation is made by the assent of all constituent parts of Parliament; the Crown, the House of Lords and the House of Commons. The authority of Parliament in this wide sense over all matters and persons within its jurisdiction was formerly unlimited.1 A statute law might be unjust or contrary to sound principles of government; but Parliament was not controlled in its discretion, and when it erred, its errors could be corrected only by itself.

In the twentieth century, however, Parliament enacted a number of statutes which curtailed its unlimited legislative authority. First, in a series of statutes beginning with the Statute of Westminster 1931,2 Parliament formally recognised limitations on its powers over the Dominions (as they were then called); and after the Second World War it conferred independence on other countries and territories within the Commonwealth. A fuller description of this process is set out in Erskine May (23rd edn, 2004), pp 63–64. Second, in 1972 it passed the European Communities Act under which the authority of European institutions to adopt measures carrying the force of law in the United Kingdom was accepted. Section 18 of the European Union Act 2011 later specified that EU law was recognised in the UK only as a result of UK legislation.3 Section 1 of the European Union (Withdrawal) Act 2018 provides that the European Communities Act 1972 will be repealed on ‘exit day’ from the European Union. A description of the effect of the European Communities Act 1972 is set out in Erskine May (24th edn, 2011), pp 184–85.

On the other hand, the legislative schema of the Human Rights Act 1998 preserves parliamentary legislative sovereignty by limiting the courts' powers, in respect of primary legislation, to making a declaration of incompatibility, rather than giving a judicial power to strike down such legislation.

Ministers are given legislative authority to make delegated legislation solely through statute. The way in which Parliament controls each type of delegated legislation will depend on the provisions of the parent statute, and is further considered in Chapter 31.


  1. 1. Instances of the courts being invited to pronounce on the unchallengeability of legislation include Martin v O'Sullivan [1982] STC 416, where the plaintiff argued that because the Social Security Act 1975 changed the status of Members of the Commons from self-employed to employed, they became salaried civil servants and so disqualified. In consequence, the 1975 Act itself was (it was contended) invalid. The court found itself incapable of making such a declaration, the judge adding (at 419) that ‘it follows from the court's inability to inquire into what passed in Parliament that it cannot ask itself whether the members of one or the other House were disqualified in some way at the material time’. Scottish courts have on occasions taken a distinctive view of the justiciability of questions of the validity of some parts of statute law. In MacCormick v The Lord Advocate 1953 SC 396, which was an action in the Court of Session to interdict Her Majesty's Ministers from publishing a proclamation regarding the royal style and title, the Lord Advocate conceded that certain parts of the Acts which created the Union of 1707 ‘could not’ be changed by subsequent legislation (at 411). The Lord President reserved his opinion on the powers of the court regarding the validity of legislation relating expressly to the Court of Session and to laws which ‘concern private right’ in Scotland and were found by the courts to be contrary to articles XVIII and XIX of the Act of Union passed by the Scottish Parliament (at 419). In the instant case, however, the court found the matter at issue one of public, not private, right. See also Gibson v The Lord Advocate 1975 SC 136, where it was held that the question whether a particular Act of the United Kingdom Parliament was ‘for the evident utility of the subjects within Scotland’ (art XVIII) was not a justiciable issue in the Court of Session. For the special position of the Church of Scotland in respect of legislation on matters spiritual, see Church of Scotland Act 1921, s 1 and sch, para IV; Stair Memorial Encyclopaedia of the Laws of Scotland (2002 re-issue) Constitutional Law, para 618; and Ballantyne v Presbytery of Wigton 1936 SC 625 and Logan v Presbytery of Dumbarton 1995 SLT 1228.
  2. 2. 22 & 23 Geo 5, c 4.
  3. 3. European Union Act 2011; ‘Directly applicable or directly effective EU law (that is, the rights, powers, liabilities, obligations, restrictions, remedies and procedures referred to in section 2(1) of the European Communities Act 1972) falls to be recognised and available in law in the United Kingdom only by virtue of that Act or where it is required to be recognised and available in law by virtue of any other Act.’