Mischief rule

The mischief rule^[1] is one of three rules of statutory interpretation traditionally applied by English courts,^[2] the other two being the "plain meaning rule" (also known as the "literal rule") and the "golden rule". It is used to determine the exact scope of the "mischief" that the statute in question has set out to remedy, and to guide the court in ruling in a manner which will "suppress the mischief, and advance the remedy".

The rule considers not only the exact wording of the statute, but also the legislators' intentions in enacting it. In applying the rule, the court is essentially asking whether parliament in enacting the statute intended to rectify a particular mischief, even though it might not be covered by a literal reading of the statute's wording. For example, if a law prohibits a specific behaviour "in the street", the legislators might – or might not – have intended the same behaviour on a first-floor balcony overlooking the roadway to be covered.

The rule was first set out in Heydon's Case, a 1584 ruling of the Exchequer Court.