The Doctrine The doctrine of precedent is based on the need for certainty in the
law. It means that lawyers can properly advise their clients on the
basis that like cases will be treated alike, rather than judges making
their own random decisions which nobody could predict. This helps
people plan their affairs. According to Lord Denning, ‘It is the
foundation of our system of case law’. However, Denning was ‘against
is its too rigid application - a rigidity which insists that a bad
precedent must necessarily be followed’.
It is the doctrine’s rigidity that can prevent developments to meet
the changing needs of society. However, this was recognised in the
House of Lords 1996 Practice Statement.
In addition, judges in the lower courts are adept at avoiding the
doctrine’s rigidity. A judge may distinguish the awkward precedent on
its facts - arguing that the facts of the case under consideration are
different in some important way from those of the previous case and
therefore the rule does not apply.
A precedent may be distinguished on a point of law; by arguing that
the legal question answered by the precedent is not the same as that
asked in the instant case.
Courts may distinguish a precedent by stating that the precedent has
been superseded by more recent decisions, and is therefore outdated.
Courts may give the precedent a very narrow ratio decidendi or argue
that the precedent has no clear ratio decidendi, for example because
the ratio of one judge in a case is different from others in the same
Courts may claim that the precedent is inconsistent with a later
decision of a higher court and has been overruled by implication; or
may state that a decision was made per incuriam.
Using these techniques, the courts have developed the law to meet
society’s changing needs in many areas, for example the right to life,
women’s and human rights generally.
A homicide defence based on necessity was not accepted in R v Dudley &
Stephens (1884) or in R v Howe a 100 years later, though it was in R v
A (Conjoined Twins) 2000. Here the issue was whether one Siamese twin