The right to freedom of religion in the United Kingdom is provided for in all three constituent legal systems, by devolved, national, European, and international law and treaty. Four constituent nations compose the United Kingdom, resulting in an inconsistent religious character, and there is no state church for the whole kingdom. The United Kingdom is a signatory to the European Convention on Human Rights (ECHR), which provides in Article 9 a right to freedom of thought, conscience, and religion; and the policy of the British government is to support religious freedom. However, the issue of absolute religious freedom has become contentious with the onset of the War on Terror.
The ECHR guarantees in Article 9 that subjects will have:
The ECHR is given binding weight in the United Kingdom by s. 1 ss. (1)(a) of the Human Rights Act 1998 (HRA), within which Article 9 (for the right to freedom of religion, etc.) of the ECHR is adopted as a "right and fundamental freedom". The HRA gives further effect in UK law to the rights for religious freedom afforded by the ECHR, and to make available in UK courts a remedy for breach of those Convention rights without the need to go to the European Court of Human Rights in Strasbourg.
In Article 18 of the International Covenant on Civil and Political Rights, which was adopted by the United Nations General Assembly in resolution 2200A (XXI) on 16 December 1966, the UN resolved that:
The United Nations Human Rights Committee, a sub-body of the General Assembly, also resolved in General comment 22 on 30 July 1993 that the right to freedom of religion applies to unconventional or extra-institutional religions, as well as atheist or anti-clerical beliefs:
The Act of Settlement 1701 decrees that the monarch of Great Britain (later the United Kingdom) "shall join in communion with the Church of England". This act was specifically designed to prevent a Catholic monarch from ascending to the throne, but in effect discriminates against all religions other than Protestantism. Members of the Royal family in line of succession who married a Roman Catholic (though not adherents of other denominations or faiths) were excluded from the succession. Under the provisions of the Succession to the Crown Act 2013, marrying a Roman Catholic no longer disqualifies a person from succeeding to the Crown; however, the provision of the Act of Settlement requiring the monarch to be a Protestant continues unrepealed.