Describe what is meant by the mischief rule

Under this rule the court is required to look at what the law was before the statute was passed in order to discover what gap or mischief the statute was intended to cover. Then courts should interpret the statute to ensure that the gap is covered and remedy the mischief.

Heydon's Case (1584) defines the mischief rule with four questions for consideration: what was common law before the Act was passed?, what was the mischief for which the existing law did not provide?, what remedy does the Act attempt to provide to cure the defect? and what is the true reason underlying the remedy?

In Smith v. Hughes, the defendant was a prostitute who had tapped on a balcony from inside a building at men passing by to attract them. It is an offence for a prostitute to solicit men in a street or public place. Lord Parker noted .. everybody knows that this was an Act intended to clean up the streets.... The mischief identified was soliciting in public and so the defendant was found guilty.

In Corkery v Carpenter the defendant rode a bicycle whilst drunk. It was an offence to be drunk in charge of a carriage. It was held the mischief was drunks on the highway and the defendant was found guilty.