Expressio Unius est Exclusio Alterius in United Kingdom

There are three rules of language applied by the courts to assist them in interpreting statutes. The rules of language are referred to as intrinsic aids or internal aids. The three rules of language are:

• the Ejusdem generis (“of the same kind”) rule,
• the Noscitur rule (Noscitur a sociis), and
• the Expressio Unius Est Exclusio Alterius rule.

Expressio Unius est Exclusio Alterius in the context of statutory interpretation

The expressio rule means that it is not necessary to add other words to the list in order to make sense of the provision. This rule is said to mean that the mention of one thing excludes another. The effect of this rule means that if a list of words is not followed by general words, the Act only applies to the words used in the list – it is not for the courts to try and second guess that Parliament meant to add other words by association. For example if a statute refers to lions and tigers it only refers to lions and tigers and will not include leopards.

In Tempest v Kilner (1846) the court had to rule whether the Statute of Frauds 1677 applied to the sale of stocks and shares. The Act required contracts for the sale of ‘goods, wares and merchandise’ to be evidenced in writing if they were above a specified value. The court decided that stocks and shares were not covered by the Act as the specific words ‘goods, wares and merchandise’ were not followed by general words.

This will not be strictly applied in the event that the Act mentions that the words listed are illustrative by the use of the word ‘includes’ for example, as this suggests that there may be other items which may apply.

Definition of Expressio Unius Est Exclusio Alterius

An act only applies to the items in a list of words, if it is not followed by general words.