28 2: Sources of law Part A Essential elements of the legal system
3.2.2 Expressio unius est exclusio alterius
To express one thing is by implication to exclude anything else.3.2.3 Noscitur a sociis
It is presumed that words draw meaning from the other words around them. If a statute mentioned
'children's books, children's toys and clothes', it would be reasonable to assume that 'clothes' meant
children's clothes.3.2.4 In pari materia
If the statute forms part of a series which deals with similar subject matter, the court may look to the
interpretation of previous statutes on the assumption that Parliament intended the same thing.3.3 Presumptions of statutory interpretation
Unless the statute contains express words to the contrary it is assumed that the following presumptions
of statutory interpretation apply, each of which may be rebutted by contrary evidence.
A statute does not alter the existing common law. If a statute is capable of two interpretations,
one involving alteration of the common law and the other one not, the latter interpretation is to be
preferred.
If a statute deprives a person of property, say by nationalisation, they are to be compensated for
its value.
A statute is not intended to deprive a person of liberty. If it does so, clear words must be used.
This is relevant in legislation covering, for example, mental health and immigration.
A statute does not have retrospective effect to a date earlier than its becoming law.
A statute does not bind the Crown. In certain areas, the Crown's potential liability is great and this
is therefore an extremely important presumption.
A statute generally has effect only in the UK. However a statute does not run counter to
international law and should be interpreted so as to give effect to international obligations.
A statute cannot impose criminal liability without proof of guilty intention. Many modern statutes
rebut this presumption by imposing strict liability, say for dangerous driving under the Road Traffic
Act.
A statute does not repeal other statutes. Any point on which the statute leaves a gap or omission
is outside the scope of the statute.3.4 Other assistance in interpretation
Intrinsic aids are those words contained in the Queen's Printer's copy of the statute. Extrinsic aids are
those found elsewhere.3.4.1 The Interpretation Act 1987
The Interpretation Act 1987 defines certain terms frequently found in legislation. The Act also states that,
unless a specific intention to the contrary exists, the use in a statute of masculine gender terminology also
includes the feminine, and vice versa. Similarly, words in the singular include plurals, and vice versa.Key terms