England, Wales and Northern Ireland
Under the common law of England, Wales and Northern Ireland, a statement was seditious under the common law if it brought into "hatred or contempt" either the Queen or her heirs, the government and constitution, either House of Parliament, or the administration of justice; or if it incited people to attempt to change any matter of Church or state established by law (except by lawful means); or if it promoted discontent among or hostility between British subjects. A person was only guilty of the offence if they had printed words or images and intend any of the above outcomes. Proving that the statement is true was not a defence. The common law offence was punishable in the UK with life imprisonment.
Parliament abolished the offence of sedition and seditious libel in 2009. However, there continue to be similar offences in other statutes, such as the Terrorism Act 2000, which criminalises threats of action which are designed to "influence the government" or "to intimidate the public or a section of the public" for "the purpose of advancing a political, religious or ideological cause".