Skip to main content

How scrutiny of treaties and treaty-making works

5 January 2020

This page describes how scrutiny of treaties and treaty-making works.

Parliamentary scrutiny of treaties and treaty negotiations is important because international agreements increasingly have a direct effect on daily life in the UK. Future trade agreements with major economies, such as the US and Japan, could affect jobs and the price and availability of goods for consumers. New agreements can also require Parliament to pass legislation to align the UK's domestic laws, or prevent Parliament from passing legislation in the future which could place the UK in breach of its international law obligations. This page sets out some of the background to how treaty scrutiny works in the UK.

What is a treaty?

A treaty is an international agreement, binding under international law, entered into by the UK, either bilaterally, when the UK enters into an agreement with another country, or multilaterally, when the UK signs up to an agreement involving three or more countries.

How were treaties made and scrutinised before Brexit?

While the UK was an EU member state, many treaties were negotiated and entered into on the UK's behalf by the EU. The UK was then a party to the EU's agreements as a member state, but not in its own right. In that context, the European Parliament was the main body that conducted treaty scrutiny. The European Parliament has significant scrutiny power, particularly after the Lisbon Treaty came into effect in 2010, when its capacities were strengthened. This includes veto power (in respect of most agreements) [Article 218(6)(a)(TFEU)], the right to propose amendments, and the right to information including consultation [Article 218 (6)(b) TFEU] by the European Commission fully and immediately at all stages of the procedure for international agreements.

In addition, while the UK was an EU Member State, draft Council Decisions (for instance, those authorising the commencement of negotiations or the adoption of negotiating guidelines) were deposited by the Government in Parliament, and were subject to scrutiny by the House of Lords EU Committee and the House of Commons European Scrutiny Committee.
In preparation for Brexit, the Lords EU Committee was tasked in January 2019 with scrutinising treaties that the Government decided to enter in its own name to replace existing EU arrangements after Brexit. These were scrutinised under the Constitutional Reform and Governance Act 2010 (CRAG).

Starting in April 2020, that task was allocated to the EU International Agreements Sub-Committee. Following the end of the post-Brexit Transition Period, the International Agreements Committee was formed out of the Sub-Committee, taking on the scrutiny of all non-EU international agreements.

What has changed after Brexit?

Treaty-making competencies have now been returned to the UK and for the first time in over 45 years it is able to negotiate treaties in a wide range of areas. These include a range of important policy areas, including trade, security, and environment.

As the UK sets out its independent trade policy following Brexit, the International Agreements Committee (IAC) has been established as a new committee to scrutinise international agreements, from negotiation to conclusion.

The House of Lords, in approving the establishment of the IAC, has given it the job of considering “the negotiation and conclusion of international agreements”. Unlike the European Parliament, committees of the UK Parliament have no statutory remit to scrutinise the negotiation of international agreements. In 2019, however, the European Union Committee, reviewing its scrutiny of Brexit-related international agreements, concluded: “During the negotiation of treaties in which Parliament has expressed a clear interest, it should be kept informed of major developments, at regular intervals, in an agreed manner.” The House's decision is the first time a committee has been given explicit responsibility to hold the Government to account in its conduct of international negotiations.

The IAC has a crucial role in ensuring agreements receive the necessary level of scrutiny. It has scrutinised the remaining 'roll over' agreements and will work to scrutinise the new treaties which the Government is seeking to enter intog. It is well placed to conduct technical and detailed scrutiny and secure time for debates on significant treaties.

Press and commentary

Lord Goldsmith QC, “International agreements affect us all. They deserve to be scrutinised” (12 February 2021): [24 May 2021]

Alexander Horne and Dominique Gracia, “Treaty scrutiny – A brave new frontier for Parliament”, UK Constitutional Law Association (18 March 2020): [14 April 2020]

Lord Kinnoull, “The Treaties Sub-Committee will be vital in ensuring trade deals and international agreements are scrutinised”, Politics Home (25 March 2020): [20 April 2020]

Lord Goldsmith, “Parliamentary scrutiny of trade agreements must no longer be an afterthought”, Politics Home (17 September 2021):