The doctrine of judicial precedent is based on stare decisis. That is the standing by of previous decisions. Once a point of law has been decided in a particular case, that law must be applied in all future cases containing the same material facts.
For example in the case of Donoghue v Stevenson[1932] AC 562, (Case summary). The House of Lords held that a manufacturer owed a duty of care to the ultimate consumer of the product. This set a binding precedent which was followed in Grant v Austalian Knitting Mills [1936] AC 85 (Case summary). Also in Shaw v DPP [1962] AC 220 (Case summary) the House of Lords held that a crime of conspiracy to corrupt public morals existed. This was followed in Knuller v DPP[1973] AC 435 (Case summary).
In order for the doctrine of judicial precedent to work, it is necessary to be able to determine what a point of law is. In the course of delivering a judgment, the judge will set out their reasons for reaching a decision. The reasons which are necessary for them to reach their decision amount to the ratio decidendi of the case. The ratio decidendi forms the legal principle which is a binding precedent meaning it must be followed in future cases containing the same material facts. It is important to separate the ratio decidendi from the obiter dicta.
The obiter dicta is things stated in the course of a judgment which are not necessary for the decision. For example in R vHowe & Bannister[1987] 2 WLR 568 Case summary the House of Lords held that the defence of duress was not available to murder. This was the ratio decidendi of the case. The House of Lords went on to consider whether the defnce should be available to those who attempt murder and stated obiter dicta that the defence of duress should not be available to attempted murder.
In addition to binding precedents, there exists persuasive precedents. These consist of judicial statements which are not binding but may be taken into account. For example, the obiter dicta from R v Howe & Bannister was followed by the House of Lords in R v Gotts [1992] 2 AC 412 Case summary which held that the defence of duress was not available to attempted murder. A form of persuasive precedent is obiter dicta. Persuasive precedents also include case law from other jurisdictions and traditionally the Privy Council decisions have been merely persuasive on the English courts. However, exceptionally the Privy Council may be binding:
There exists a hierarchy of the courts. The basic rule is that a court must follow the precedents from a higher court, but they are not bound to follow decisions from courts lower in the hierarchy. A basic outline of the hierarchy is:
*
European Court of Justice
**
Supreme Court (formerly House of Lords)
***
Court of Appeal
****
Divisional Courts
*****
All other courts (County, Crown, Magistrates, tribunals - these have no power to create precedents)
Where the precedent was set by a court of the same level, the court is generally bound by the previous decision, but this is subject to exceptions. Different considerations apply depending on the level of court as to whether the court may depart from a previous decision of a court of the same level.
European Court of Justice
The European Court of Justice does not recognise the doctrine of precedent and is free to depart from its own previous decisions.
House of Lords/Supreme Court
The House of Lords was replaced by the Supreme Court from 1st October 2009. The Supreme court will exercise the same jurisdiction as the House of Lords and the Law Lords will take office as Justices of the Supreme Court.
At one time the House of Lords were absolutely bound by their own previous decisions:
However, in 1966 the Lord Chancellor, Lord Gardiner, issued a Practice Statement allowing the House of Lords to depart from a previous decision where it appears right to do so:
Practice Statement HL Judicial Precedent [1966] 1 WLR 1234
Whilst the House of Lords had this power they were reluctant to use it:
In considering whether to use the 1966 Practice Statement the House of Lords needs to be mindful of the retrospective effect of their decisions (See declaratory theory below for more info). In Cunningham[1982] AC 566 Case summary the House of Lords refused to overrule the previous decision of R v Vickers [1957] 2 QB 664 Case summary because of the retrospective effect it would have on those convicted of murder and had been subject to the death penalty.
Cases where the House of Lords have used the Practice Statement:
The Court of Appeal is bound by judgments from the ECJ, the House of Lords and Supreme Court. It is generally bound by its own previous decisions however this is subject to the exceptions set out in Young v Bristol Aeroplane:
Young v Bristol Aeroplane Co Ltd [1944] KB 718 Case summary
However, greater flexibility is afforded to the Criminal Division of the Court of Appeal:
Lord Denning was critical of the constrainst operating on the Court of Appeal and wished to have the same power to depart as enjoyed by the House of Lords. He attempted to evade the rule in Young v Bristol Aeroplane in the Court of Appeal in Davis v Johnson. However, on appeal to the House of Lords, the Lords were critical of Denning's approach and affirmed that the 1966 Practice Statement was for the exclusive use of the House of Lords:
