Treaty

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A formal international agreement between states or international organisations.

Category: Devolution and constitution Parliamentary documents and sources

Also used as: treaties, international treaty, international treaties, treaty agreement, international agreement, international agreements

Source / explainer: Read GOV.UK guidance on UK treaties

Last reviewed: 21 August 2026

A treaty is a formal international agreement between states or international organisations. In the UK, treaties are negotiated and ratified by the Government, but Parliament has a scrutiny role for treaties laid under the Constitutional Reform and Governance Act 2010. Treaties can matter where international commitments affect domestic law, foreign policy, trade or security.

Related terms

Command PaperA government paper formally presented to Parliament.Foreign, Commonwealth and Development OfficeThe UK Government department responsible for foreign affairs, diplomacy, development and overseas relations.
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