Currently, Parliament’s role in treaty making is limited to scrutinising treaties under the provisions of the Constitutional Reform and Governance Act 2010 (CRAG). This Act partially codifies, and to a limited extent progressively develops, the ‘Ponsonby Rule’ relating to the ratification of treaties (a convention which dates back to 1924). It is under section 20 of this Act that the House of Lords motion on the UK-Rwanda Agreement has been made.

CRAG requires new international agreements subject to ratification to be laid before Parliament for 21 sitting days and requires the Government to provide explanatory memoranda about new treaties. It also provides the House of Commons with a theoretical device to delay the ratification of new treaties. But it does not make any specific provision for scrutiny. Nor does it provide for any route to a debate, or vote, rendering this power of delay essentially illusory, given that the Government controls parliamentary time.

Since the introduction of the Ponsonby rule, almost a century ago, the scope, depth and mechanics of commitments under international agreements have changed considerably. Trade agreements are emblematic of this change: agreements once focused on tariffs on the trade in goods now encompass detailed regulatory obligations, ranging from intellectual property law to subsidies. They often set up treaty bodies with the power to develop the treaty in some limited manner.

In light of these changes, the former chair of the International Agreements Committee, Baroness Hayter, has concluded that the existing legislation on treaty scrutiny is “not fit for purpose”.

In the new report, we argue that the changed landscape of international agreements challenges the UK treaty scrutiny system in two ways.

First, it raises questions regarding legitimacy. Parliaments play an important role in the democratic legitimation of international agreements, including free trade agreements. Many jurisdictions require a parliamentary consent vote on some treaties, including trade agreements (often in the form of an up-or-down vote). The current UK system fails to provide that legitimacy. The report shows that Parliament’s involvement in scrutinising treaties and in passing implementing legislation no longer suffices in the light of the way modern treaties are drafted and implemented.

Second, the complexity of modern treaties imposes pragmatic challenges for treaty scrutiny. Over time, it has become evident that these expansive modern free trade agreements cannot be examined in a meaningful way under the current system.

The need to replace the EU’s trade agreements provoked some reform of internal parliamentary procedures in the UK. However, the framework for scrutiny is still inadequate, particularly in the House of Commons, which has no real dedicated scrutiny mechanism in place. Although the government has made a number of post-Brexit commitments concerning the scrutiny of new free trade agreements, it is doubtful whether these go far enough to provide adequate accountability and they do not apply to other significant treaties which do not relate to trade.

In 2020, Parliament established a formal treaty scrutiny mechanism in the House of Lords European Union Committee. In January 2021, this became a stand alone select committee: the International Agreements Committee (IAC). The IAC has now gained considerable experience in handling treaties and we believe that the time has now come to learn from this experience and reform the UK treaty scrutiny system to properly bring it into the 21st century.

In the report, we have proposed a number of reforms to improve the practice of treaty scrutiny.

These recommendations consist of five main elements:

1. systematic scrutiny of treaties in both Houses of Parliament;

2. the introduction of a parliamentary consent vote in the House of Commons for significant treaties, particularly new free trade agreements (FTAs);

3. ensuring the early involvement of Parliament, starting with the negotiating mandate for FTAs;

4. broadening the list of documents subject to scrutiny (to include certain Memoranda of Understanding and amendments); and

5. to cope with the increased workload, introducing a sifting mechanism (that would be conducted in a new Sifting Committee in the House of Commons and continue to be conducted in the IAC in the House of Lords) to identify treaties requiring thorough parliamentary engagement.

Reform of this sort would not just strengthen the legitimacy of treaties the UK becomes a party to, it would also have the potential to improve outcomes and thereby benefit the UK as a whole.

A. Horne & H. Hestermeyer (22 January 2024), How should Parliament scrutinise new treaties? (Hansard Society blog)