In Britain we have what is known as a “common law” legal system. Decisions made by higher courts are binding on the courts below them in accordance with the system of “judicial precedent”. In civil and criminal proceedings, the role of the judge or magistrate is to apply the law to the facts in any particular case. However this is not always easy as legislation is often ambiguous and open to different interpretations. In such cases it is the job of the higher courts to decide how legislation is to be interpreted. Their decision is then binding on all future cases, where the facts are sufficiently similar.
A common law system is a legal system that gives great potential precedential weight to common law, on the principle that it is unfair to treat similar facts differently on different occasions. In cases where the parties disagree on what the law is, a common law court looks to past precedential decisions of relevant courts. If a similar dispute has been resolved in the past, the court is bound to follow the reasoning used in the prior decision (this principle is known as stare decisis*). If, however, the court finds that the current dispute is fundamentally distinct from all previous cases (called a “matter of first impression”), judges have the authority and duty to make law by creating precedent. Thereafter, the new decision becomes precedent, and will bind future courts.
There are some criminal offences which are known only as “common law” offences. These are offences which have been developed entirely by the courts over the years, and for which there is no actual legislation. Examples of common law offences are murder, perverting the course of justice and causing a public nuisance and causing a breach of the peace.
The House of Lords is the highest court in the land and its decisions on both civil and criminal cases are binding on all other domestic courts. Next down are the civil and criminal divisions of the Court of Appeal, which is bound by the House of Lords, but binds all courts below. Then there are the civil and criminal divisions of the High Court. Its decisions only bind the Crown and magistrates courts. The lowest courts – the Crown and magistrates court for criminal and the County Court for civil cases– cannot bind any other court.
“Common Law” originated in England in the Middle Ages and is used particularly here and in former colonies of England, sometimes mixed with civil law.
* Latin (Stare decisis et non quieta movere: “to stand by decisions and not disturb the undisturbed”)