3.5 Common law
This may be a familiar term that you have encountered in newspaper reports or on the television or radio. Common law has its roots in history. In 1066, William the Conqueror began to establish a strong central government and to standardise the law in England. Representatives of the King were sent out into the country to check the local administration and were given the job of adjudicating local disputes according to local law. When these individuals returned to London they were able to discuss the various local laws from different parts of the country and began to use those that seemed rational to form a consistent body of laws. By about 1250 a common law had been produced that applied to the whole country. It could be applied consistently and could be used to predict what the courts might decide in particular cases.
Common law now, in effect, comes from case law, that is, the decisions made by judges in the court cases they judge. When considering a court case a judge has two tasks: first, establishing what the facts are (what actually happened), and second, how the law applies to those facts. It is the second aspect that makes case law. Once the decision has been made on how the law applies to a particular set of facts, later cases with similar facts should be treated in the same way. This is known as a system of judicial precedent. This means that in any decision there is a ratio decidendi – the reason for deciding. This is the principle of law on which the facts of the case have been decided.
Common law is created by a system which relies on a court hierarchy. This means that courts lower down in that hierarchy (such as the Magistrates' Courts, Crown Court, County Court or High Court) are bound by the decisions made by the higher courts (such as the House of Lords).