Discuss the advantages and disadvantages of the operation of the mischief rule

The mischief rule avoids absurd and unjust outcomes. For example, it is an offence to operate a live sex venue without a licence from the local authority. The Act referred to performances which were not unlawful. In McMonagle v Westminster City Council, the defendant argued the performances were unlawful and therefore his conviction for not having a licence should be overturned. The House of Lords decided to ignore the words not unlawful and the guilty verdict was upheld.

The rule is flexible which leads the law to be applied as intended by Parliament rather than just applying the law as stated by Parliament. This is illustrated by Smith v. Hughes, where the intention was clear as noted by Lord Parker .. everybody knows that this was an Act intended to clean up the streets.....

The Law Commission's Report on Interpretation of Statutes (1969) endorsed this approach as .. rather more satisfactory... than other rules.

Although it can be argued it is an outdated approach. It was established in Heydon's Case (1584) when the legal system was different in a number of important ways. At that time common law was the main source of law, parliamentary supremacy was not so established, Acts contained lengthy preambles which spelt out the mischief it aimed to remedy, judges usually drafted Acts on behalf of the King and drafting was less exact.

The rule allows for judicial law making which can be argued is undemocratic as it gives power to decide to unelected judges. Infringement on the role of legislators is illustrated in Royal College of Nursing v DHSS where Lord Edmund-Davies stated .. redrafting with a vengeance... of the Abortion Act 1967 was necessary to protect a large number of nurses who otherwise would have been performing illegal abortions.

Also it can often be difficult to identify the mischief as shown in Attorney General v Associated Newspapers Ltd a case about disclosure of jury deliberations. This can lead to further uncertainty and power in interpretation given to judges.