Georgetown Law
Georgetown Law Library

United Kingdom Legal Research Guide

This in-depth guide will help researchers navigate legal materials for the United Kingdom.

UK Treaties & International Agreements

Background Information on UK Treaties

UK Treaty Practice & Procedure

The Foreign, Commonwealth & Development Office (FCDO) is the cabinet department responsible for drafting treaty texts and instruments of ratification.  Consult the following FCDO resources for information about UK treaty practice:

  • Overview of UK Treaty Practice and Procedures
    This page on the FCDO website provides a brief overview of UK treaty practice and procedure.
  • Treaties and Memoranda of Understanding (MOUs)
    This FCDO publication provides more detailed guidance, including information about the process by which UK treaties are ratified and a glossary of treaty terminology.
  • UK Treaty Action Bulletins (2013-Present)
    This monthly publication summarizes recent actions taken by the UK with respect to multilateral treaties (signature, ratification, and entry into force), as well as changes to the status of multilateral treaties for which the UK serves as the depositary.

Publication of UK Treaties

Basic information about the publication of UK treaties is provided below.

Initial Publication Prior to Entry Into Force
Under Chapter 2 of the Constitutional Reform and Governance Act of 2010, the text of a treaty must be "laid before" both houses of Parliament in the form of a command paper before it can enter into force.  The FCDO publishes command papers in one of the following series:

  • Country Series -- for bilateral treaties
  • Miscellaneous Series -- for multilateral treaties
  • European Union Series -- for treaties between the member states or between the EU and other states

Republication After Entry Into Force 
After a treaty enters into force, it is republished in the United Kingdom Treaty Series.  Since 1892, all UK treaties that have entered into force have been published in this series.  Most, but not all, UK treaties also are published in the U.N. Treaty Series upon entry into force.

Citations to UK Treaties

Citations to treaties to which the U.S. is not a party are governed by Rule 21.4.5 (b) of The Bluebook, KF245 .U5 2020.  According to this rule, a citation to a treaty source published by an international organization, such as the U.N. Treaty Series, is preferred, if the treaty was published therein.  If not, then cite to the U.K. Treaty Series (for treaties that have entered into force) or to the relevant command paper series (for treaties that have not entered into force).

The UK as a Treaty Depositary

The UK serves as the depositary institution for more than four dozen multilateral treaties.  In this role, the UK acts as the custodian of the treaty texts and also maintains current lists of all state parties to each treaty and records of any reservations or declarations made by each state party.  A current list of treaties, organized by subject, for which the UK serves as the depositary is available in this page of the FCDO's website.

Electronic Access to UK Treaties (1892-Present)

The UK has digitized the full texts of treaties published in the U.K. Treaty Series.  As a result, most UK treaties that have entered into force since the series began publication in 1892 are accessible online in PDF format.  As with any large-scale digitization project, there may be some gaps in coverage.  Use the electronic resources described below to access UK treaties online.

  • UK Treaties Online (UKTO)
    This free database includes records for more than 15,000 multilateral and bilateral treaties to which the UK is (or has been) a party.  Use the Advanced Search to search by treaty title and limit by date of signature, date of entry into force, place of signature, treaty type and treaty partner.  For guidance, consult the User Guide and the Search Hints & ExamplesNote:  Treaties signed by the UK that have not yet (or never) entered into force are not included in this database.
    • Treaty Records 
      The database includes records for UK treaties concluded from 1783-present.  Each record provides basic information, including the type of treaty, the place and date of signature, and a list of countries that have signed and/or ratified the treaty.
    • Links to Full Texts of Treaties
      Links to the full texts of treaties, as published in the U.K. Treaty Series, are available for treaties that entered into force from 1892-2001.  For treaties that entered into force after 2001, a link is provided to the command paper containing the full text of the treaty.
  • Quick Links to Recent UK Treaties
    The FCDO's website provides quick links to UK treaties that have entered into force and been published in the UK Treaty Series from 2013 onward.  Treaties that have recently entered into force are are arranged in two groups:  2013-2017 and 2018-Present.  Browse chronologically by year.  Note:  This is not a searchable database. 
  • U.N. Treaty Series Online (1946-present).  Also available on HeinOnline.
  • League of Nations Treaty Series Online (1920-1946).  Also available on HeinOnline.
    In addition to being published in the U.K. Treaty Series, most UK treaties that have entered into force also are published in the U.N. Treaty Series (U.N.T.S.) or in its predecessor series, the League of Nations Treaty Series (L.N.T.S.). If you can't find the treaty you are seeking in UK Treaties Online (described above), try searching the U.N.T.S. or, if appropriate, the L.N.T.S.
  • UK Treaties Not Yet Entered Into Force (1999-Present)
    This page of the FCDO's website provides links for accessing the full texts of bilateral and multilateral treaties that have been signed by the UK but not yet entered into force from 1999-present.  (Scroll down to the heading "Treaties that have been signed but not yet ratified (or equivalent.)"  Texts of treaties that have not entered into force are published as command papers presented to Parliament.

U.K. Treaty Series on Microfilm

The Georgetown Law Library has the complete United Kingdom Treaty Series on microfilm.  This series includes the full texts of treaties that entered into force from 1892-present.  To the extent that there are any gaps in coverage in the electronic resources described above, the microfilm set can be used as a backup.  Ask a reference librarian if you need assistance in locating the microfilm or using the microfilm readers.

Historical UK Treaties (Prior to 1892)

Use the resources described below to identify and locate UK treaties that entered into force prior to 1892, when the U.K. Treaty Series began publication.

Finding Aid

  • An Index of British Treaties:  1101-1968.  Call No.  REF KZ635 .P37 1970
    This comprehensive four-volume set includes annotations and citations to print sources.

Print & Electronic Sources

  • Avalon Project (Yale Law Library)
    This free resource provides online access to selected diplomatic papers and historical treaties, including many British treaties.  Browse chronologically or alphabetically by document collection.  Or search by keyword using the search box in the upper right-hand corner.
  • British and Foreign State Papers.  Call No.  KZ631 .G74 (1812-1977)
    Digitized version available on HeinOnline (1812-1968)
    This series includes the full texts of selected treaties and diplomatic papers from the UK and other countries.
  • Hertslet's Commercial Treaties.  Call No. KZ636 .G74 1910
    This multi-volume collection of UK commercial treaties was published separately as a stand-alone series before being incorporated into the British Foreign and State Papers.
  • A Collection of All the Treaties of Peace, Alliance, and Commerce Between Great-Britain and Other Powers, From the Treaty Signed at Munster in 1648, to the Treaty Singed in Paris in 1783.  Call No. KZ636 .C6 1785r.  Volume I covers the period from 1648-1713.  Volume II covers 1713-1748, and Volume III covers 1748-1783.  Digitized version available on HeinOnline.