Introduction
The common law is the law declared by judges, derived from custom and precedent. It originated with the legal reforms of King Henry II in the 12th century and was called “common” because it applied equally across the whole country. The doctrine of binding precedent, whereby courts follow and apply the principles declared in previous cases decided by more senior courts, known as “courts of record”, is also known by the Latin expression “stare decisis”.
The common law includes both substantive rules, such as the offence of murder, and procedural ones, such as court procedure rules derived from the inherent jurisdiction of the court.
Common law rules may be superseded or replaced by legislation, which is said to “trump” or take precedence over the common law. Offences of theft, for example, based on the old common law offence of larceny, are now governed by the Theft Acts 1968, 1978 etc; and the original penalties for murder (though not the offence itself) were replaced by statutes such as the Homicide Act 1957.
There is a limit to the extent to which common law judges, however creative or “activist”, can reform an out-of-date law, particularly if it derives from a statute. In such circumstances, only Parliament can change the law. The need for such a change often follows a period of research and consultation by the Law Commission, which was set up to review and propose reform to old or inadequate laws.