English law, the legal system of England and Wales, is the basis of common law legal systems throughout the world (as opposed to civil law or pluralist systems in other countries, such as Scots law). It was exported to Commonwealth countries while the British Empire was established and maintained, and it forms the basis of the jurisprudence of most of those countries. English law prior to the American revolution is still part of the law of the United States, except in Louisiana, and provides the basis for many American legal traditions and policies, though it has no superseding jurisdiction.
The essence of English common law is that it is made by judges sitting in courts, applying their common sense and knowledge of legal precedent (stare decisis) to the facts before them. A decision of the highest appeal court in England and Wales, the House of Lords, is binding on every other court in the hierarchy, and they will follow its directions. For example, there is no statute making murder illegal. It is a common law crime - so although there is no written Act of Parliament making murder illegal, it is illegal by virtue of the constitutional authority of the courts and their previous decisions. Common law can be amended or repealed by Parliament; murder, by way of example, carries a mandatory life sentence today, but had previously allowed the death penalty.
England and Wales are constituent countries of the United Kingdom, which is a member of the European Union and EU law is effective in the UK. The European Union consists mainly of countries which use civil law and so the civil law system is also in England in this form, and the European Court of Justice, a predominantly civil law court, can direct English and Welsh courts on the meaning of EU law.
The oldest law currently in force is the Distress Act 1267, part of the Statute of Marlborough, (52 Hen. 3). Three sections of Magna Carta, originally signed in 1215 and a landmark in the development of English law, are still extant, but they date to the reissuing of the law in 1297.