Common law offences are crimes under English criminal law and the related criminal law of other Commonwealth countries. They are offences under the common law, developed entirely by the law courts, and therefore have no specific basis in statute.
Under the criminal law of Australia the Criminal Code Act 1995 (Cth) abolished all common law offences at the federal level. The Australian Capital Territory, the Northern Territory, Queensland, Tasmania and Western Australia have also abolished common law offences, but they still apply in New South Wales, South Australia and Victoria. Although some common law offences still exist in New South Wales, many common law offences - for example nightwalking, riot, rout, affray, keeping of bawdy houses, champerty and maintenance, eavesdropping and being a common scold - have been abolished in that State.
In Canada the consolidation of criminal law in the Criminal Code, enacted in 1953, involved the abolition of all common law offences except contempt of court (preserved by section 9 of the Code) and contempt of Parliament (preserved by section 18 of the Constitution Act, 1867).
In England and Wales, the Law Commission's programme of codification of the criminal law included the aim of abolishing all the remaining common law offences and replacing them, where appropriate, with offences precisely defined by statute. Common law offences were seen as unacceptably vague and open to development by the courts in ways that might offend the principle of certainty. However, neither the Law Commission nor the UK Parliament have completed the necessary revisions of the law, so common law offences still exist. In England and Wales common law offences are punishable by unlimited fines and unlimited imprisonment.
Extant common law offences are listed at English criminal law § Common law offences, and those that have been abolished or redefined as statutory offences are listed at History of English criminal law § Common law offences.
This list includes offences that have been abolished or codified in one or more or all jurisdictions:
In New Zealand the ability to be proceeded against at common law for being a party to a criminal offence was abolished by section five of the Crimes Act, 1908. The Crimes Act, s9, 1961 (which replaced the 1908 enactment) affirmed the abolition of criminal proceedings at common law, with the exception of contempt of court and of offences tried by courts martial.
The notion that common law offenses could be enforced in federal courts was found to be unconstitutional by the U.S. Supreme Court in United States v. Hudson and Goodwin, 11 U.S. 32 (1812). A woman, Anne Royall, was nonetheless found guilty of being a common scold in Washington, D.C. in 1829; a newspaper paid her fine. Some have argued that common law offences are inconsistent with the prohibition of ex post facto laws.
At the state level, the situation varies. Some states, such as New Jersey, have abolished common law crimes (see State v. Palendrano), while others have chosen to continue to recognize them. In some states, the elements of many crimes are defined mostly or entirely by common law, i.e., by prior judicial decisions. For instance, Michigan's penal code does not define the crime of murder: while the penalties for murder are laid out in statute, the actual elements of murder, and their meaning, is entirely set out in case law.