1. Scrutiny of international agreements by Parliament

Treaties are international agreements concluded in writing between nation states which create rights and obligations in international law. In the UK, treaty-making is a function of the government under the royal prerogative. There is no systematic scrutiny function for the UK Parliament during the negotiation and agreement of a treaty. However, Parliament does have a role in the process of ratification. Since 1924 there has been a convention (known as the Ponsonby rule) that, once signed, treaties are laid before Parliament for 21 days before they can be ratified. In 2010, this convention was placed on a statutory footing in part 2 of the Constitutional Reform and Governance Act 2010 (CRAG Act 2010). However, no debate or vote in either House of Parliament is required prior to a treaty being ratified. The House of Commons has the power to delay ratification for 21 days—repeatedly, if desired—but only if the government makes time for debates and votes. The House of Lords can vote against ratification, but the government can still proceed by making a statement setting out why it believes the treaty should be ratified.

In addition to procedures under the CRAG Act 2010, Parliament may need to pass legislation to implement an international agreement in domestic UK law. The UK is a dualist state. This means that international treaties do not automatically become part of its domestic law. In instances where agreements (or parts thereof) need to be implemented in domestic law, Parliament will need to pass legislation. UK courts have no power to enforce treaty rights and obligations unless legislation is passed to implement the relevant treaty provisions into domestic law. Foreign, Commonwealth and Development Office (FCDO) guidance on treaties says that if domestic legislation is needed to enable the UK to give effect to its obligations under a treaty, the legislation should be in place before the treaty comes into force, so that the two can come into operation at the same time. The FCDO therefore usually insists that any necessary UK legislation is in place before a treaty is ratified or acceded to.

Whilst the Trade (Australia and New Zealand) Act 2023 implements the procurement provisions of the Australia and New Zealand free trade agreements (FTAs) in domestic law, the Procurement Bill (which is currently awaiting report stage in the Commons) would provide a power to implement the UK government’s procurement market access obligations in trade agreements in future.

2. Trade agreements

The negotiation of new trade agreements has been a key part of the UK government’s post-Brexit policies. Parliament’s role in this process has therefore come under focus.

Whilst there are no statutory requirements for it to involve Parliament directly in the negotiation process, the government has made commitments on facilitating parliamentary scrutiny. On 19 May 2022, the government set out its commitments to parliamentary scrutiny of trade agreements in an exchange of letters with the chair of the House of Lords International Agreements Committee, Baroness Hayter of Kentish Town (Labour). This included scrutiny during pre-negotiations, during negotiations and post signature.

There are also provisions under the Agriculture Act 2020 that may need to be complied with before an FTA can be laid before Parliament under the CRAG Act 2010. Under section 42 of the Agriculture Act 2020 (subject to certain conditions), if an FTA includes measures applicable to trade in agricultural products, the secretary of state must lay a report before Parliament explaining whether the measures are consistent with UK levels of statutory protection in relation to human, animal or plant life or health, animal welfare and the environment. The treaty may not be laid before Parliament under the CRAG Act 2010 until the section 42 report has been laid. The Trade Act 2021 amended section 42 of the Agriculture Act 2020 to require the secretary of state to request advice from the Trade and Agriculture Commission in relation to the above matters (except human life or health) and to lay this advice before Parliament.

3. Parliamentary committees

The House of Lords International Agreements Committee scrutinises all treaties that are laid before Parliament under the CRAG Act 2010. It also considers ongoing negotiations.

In the House of Commons, international trade agreements would typically be scrutinised by the International Trade Committee, which is conducting an ongoing inquiry into the UK’s trade negotiations. The House of Commons Public Administration and Constitutional Affairs Committee has been conducting an inquiry into the scrutiny of international treaties and other international instruments. The inquiry has a particular focus on the role of the House of Commons.

Parliamentary committees have expressed concern about the level of parliamentary scrutiny of international treaties. For example, the House of Lords Constitution Committee considered the CRAG Act 2010 in a report published in April 2019. Amongst its conclusions, the committee argued that the act’s provisions for enabling parliamentary scrutiny of treaties were “limited and flawed” and that reform was needed to allow for effective scrutiny. In its response to the report, the government said that the CRAG Act 2010 remained a “viable legal framework for scrutiny”, but it agreed that “improvements can be made to the operation of the scrutiny mechanisms and processes within that framework, and that information provision between the executive and Parliament can also be improved”.

In September 2021, the House of Lords International Agreements Committee published a report on its experiences scrutinising agreements under the current statutory framework for treaty scrutiny. Among its recommendations, the committee called for government commitments on scrutiny working practices made since April 2020 to be consolidated in a formal concordat. The committee also asked the government to commit to giving it more notice of both treaties set to be laid before Parliament and other significant agreements. In a debate in the House of Lords, Baroness Hayter, chair of the International Agreements Committee, said that the May 2022 exchange of letters is not a concordat but the committee and the government had “got there” and “reached a compromise”.

On FTAs specifically, the House of Commons International Trade Committee has been critical of the scrutiny process for the Australia FTA. In its October 2022 report on the parliamentary scrutiny of FTAs, the committee noted that the House of Commons “was not granted a meaningful opportunity to debate the Australia FTA and our report, nor the chance to vote on whether to delay ratification”. The objection period under the CRAG Act 2010 for the Australia agreement ended on 20 July 2022. The period for the New Zealand FTA ended on 1 December 2022. A general debate on both the UK-Australia and UK-New Zealand FTAs was held in the Commons on 14 November 2022.

4. Read more

The House of Lords Library has published a briefing which looks at the House of Lords International Agreements Committee’s September 2021 report on its working practices. This was one year on from an initial report published in July 2020:

The House of Lords debated the report on 19 May 2022.


Cover image by Dominika Gregušová on Pexels.