Parliamentary sovereignty may be considered to be the fundamental rule of the UK legal system. In brief, parliamentary sovereignty states that Parliament can enact any law whatsoever and the courts may not question an Act of Parliament or rule it to be invalid.
However, this traditional model of parliamentary sovereignty is sometimes questioned. This is because the courts occasionally act in a way which appears to breach it. For instance, the courts have ruled that certain provisions in Acts of Parliament (often known as ouster, or preclusive, clauses) which appear to limit or exclude the courts’ jurisdiction on a particular matter do not, in fact, have that consequence. This was the result in the well-known case: Anisminic v Foreign Compensation Commission. Likewise, in the Factortame case, the Appellate Committee of the House of Lords granted an injunction to prevent parts of the Merchant Shipping Act 1988 from taking effect.
Supporters of the traditional view of parliamentary sovereignty often argue that, in cases such as these, the courts are not ruling in a way which runs contrary to the Act of Parliament; rather, the courts are complying with what Parliament must have intended.
Other commentators argue that cases such as Anisminic and Factortame demonstrate that there are limits to the legislative competence of Parliament which the courts will uphold. Such arguments are supported by comments from some (but by no means all) judges to the effect that parliamentary sovereignty is not absolute.
Dr John McGarry, Reader in Law at Edge Hill University, has argued that the decisions of the courts, along with the suggestion of some members of the judiciary, indicate that there are limits to Parliament’s legislative competence. However, he argues that these limits are not fixed and do not operate in a hard-and-fast way. He contends that the evidence demonstrates that parliamentary sovereignty operates like a principle and, because of this, individual Acts of Parliament may be balanced against other conflicting principles. In some cases, an Act of Parliament will be held to outweigh any conflicting principles whereas, in others, the principle will take precedence over the statute. Which will take precedence in any particular case will depend on a number of factors, including: the importance of the conflicting principle; the language used in the legislation; and the degree of infringement of the principle that the legislation represents.
Dr McGarry’s arguments on this matter have been published in ‘The Principle of Parliamentary Sovereignty’, which has been published in the academic journal Legal Studies.