Note: This is part three of a three-part series on the proposed handover of the Chagos Archipelago from the UK to Mauritius.
Part one — Why the Proposed UK-Mauritius Handover Would Be a Strategic Blow to Western Security — can be found here.
Part two — Why the Proposed UK-Mauritius Handover Is Not Required by International Law — can be found here.
The Chagos Archipelago is an island chain in the middle of the Indian Ocean that has been under continuous British sovereignty since 1814. Further, even though the Archipelago was never part of an independent Mauritius and even though the Chagossians who lived on the island before are not of Mauritian descent and have expressed a desire to remain under British sovereignty, Mauritius has recently benefitted from a series of international pronouncements that have been used to support its claim to sovereignty over the Archipelago.
Those pronouncements were a blow to a beleaguered United Kingdom that has lost much diplomatic influence in recent years through entrenched economic and political mismanagement by successive governments. No doubt, there was much merit to claims that the (non-indigenous but long-resident) Chagossian Islanders were badly treated by historic British governments. However, as explained in a previous article in this series, the Archipelago remains of vital strategic importance to the West and the end of British sovereignty would diminish the Western presence in the region and serve as a potential enabler to rival powers. Moreover, as explained in another piece, the international pronouncements supporting the Mauritian claim are not legally binding on the UK. Therefore, the recent plan of the British government to hand sovereignty of the Chagos Archipelago to Mauritius would be an unforced mistake.
Fortunately, the deal is not yet done as its terms remain unsettled by the respective governments. Further, even if the UK government wishes to press ahead with the deal in 2025 (against the will of the incoming American administration, the treaty must pass the ratification procedures of the UK parliament). Here, the deal is likely to receive substantial criticism and efforts to delay and/or block ratification may be mounted. As will be explained here, parliamentarians can leverage the “Ponsonby Rule” to frustrate the government’s efforts to finalise the proposed agreement provided they can secure sufficient backing to force a debate on the issue.
Government Treaty Making and Parliament’s Ponsonby Rule
In the UK, the negotiation and execution of treaties with other States is largely the prerogative of government. As the House of Commons library notes, “the UK Government is responsible for negotiating, signing, ratifying, amending and withdrawing from all international treaties involving the UK, under its prerogative powers.” More formally, “the power to make treaties is a Prerogative power vested in the Crown. It is exercised on the advice of the Secretary of State for Foreign and Commonwealth Affairs, who, in turn, consults with other Departments of Government whose responsibilities would be engaged in executing the provisions of particular treaties.” The British position can be contrasted with that in the United States where the constitution provides that “[the President] shall have Power, by and with the Advice and Consent of the Senate, to make Treaties, provided two thirds of the Senators present concur.”
Although the British government has control of the lion’s share of the treaty making process, its power is not entirely unfettered. In particular, the government’s power to progress treaties is inhibited by the constitutional convention known as the Ponsonby Rule, which was followed for eighty years without controversy, and was enshrined in legislation vis-à-vis the Constitutional Reform and Governance Act 2010 (CRGA). The Ponsonby Rule provides that the government cannot ratify a treaty unless it has first laid the signed treaty before Parliament for 21 sitting days.
The “laying” is achieved by means of a Command Paper published in one of the following Foreign, Commonwealth and Development Office series: Country, Miscellaneous or European Communities. The proposed treaty must be accompanied by an “Explanatory Memorandum” that articulates its purpose, benefits and burdens. As a matter of practice, the Foreign, Commonwealth and Development Office sends a copy of the treaty and the Explanatory Memorandum to the Foreign Affairs Committee, the International Agreements Committee and to other relevant select committees and government departments. This modern position would help to assuage the fears of Arthur Ponsonby (Under-Secretary of State for Foreign Affairs in the 1920s and namesake of the Ponsonby Rule) about the lack of “treaty-making transparency and the sidelining of Parliament [through] a secretive and politically detached foreign policy machinery.”
After the laying of the draft treaty, the House of Lords and/or the House of Commons may then request a debate on the proposed treaty. If a resolution is passed by the House of Lords during the 21-day period resolving that the treaty should not be ratified, it can still be ratified if a government minister lays a statement indicating that they are of the opinion that the treaty should nevertheless be ratified and explaining why. However, if the House of Commons resolves against the treaty, the treaty cannot be ratified and another 21-sitting-day delay is triggered, allowing the government to make its case again and creating space for further Commons debate. This government/Commons ping pong can continue until either (i) the government withdraws the treaty or (ii) the Commons through action or silence allows ratification. Given that the Ponsonby Rule operates via an objection-based model, it has been described as a “negative procedure:” in other words “the government can go ahead unless Parliament objects.” Thus, the House of Commons has the power, in theory, to delay indefinitely the ratification of a treaty.
The Practical Difficulty of Securing a Debate on Treaty Ratification
Based on the above, one might reasonably take the view that the UK parliament, especially the House of Commons, holds great sway over the ability of the government to ratify treaties. However, there is a substantial procedural limitation to parliament’s ability to frustrate treaty ratification: its right to secure a debate. Arthur Ponsonby, the architect of the Ponsonby Rule, took the view that “if there is a formal demand for discussion forwarded through the usual channels from the Opposition or any other party, time will be found for the discussion of the Treaty in question.” Somewhat more recently, according to the House of Commons Information Office, “once Parliament has been presented with the text of an important or controversial treaty it is difficult in practice for the Leader of the House to resist a debate on it.” Similarly, it observed that even “on occasions when the opposition front bench does not make a formal request for a debate, it is possible for backbenchers to secure a debate in private members’ time.” Notably though, there is no dedicated formal mechanism that allows parliamentarians to force a debate on the ratification of a controversial treaty.
This lack of a formal mechanism to trigger debates over controversial treaties has drawn criticism.
As noted by the Hansard Society, “one shortcoming of current UK parliamentary ratification consent arrangements is that … the route to a debate and vote on a ratification disapproval motion is not clear or guaranteed, and is certainly largely untested.” Similarly, it has been observed that this procedural lacuna benefits the government as “opportunities for debate on the floor of the House of Commons depend, to a significant extent, on the willingness of the Government to facilitate them because it controls most of that time.” Thus, “we might find out that formal procedural arrangements for Parliament’s pre-ratification consent are inadequate only once a politically controversial treaty is upon us.” The potential shortcomings of the Ponsonby Rule, in its modern day CRGA formulation, were explored by the House of Lords Constitution Committee in 2019. The Committee reported 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 lieu of a dedicated mechanism to force a debate on a treaty ratification, Members of Parliament must try to rely on an existing route to debate. Of course, time is limited in the House of Commons and so none of these options are guaranteed. For example, one way for backbench (i.e. non-government) members of the House of Commons to request a debate on a controversial treaty is to table an “Early Day Motion” (i.e. a suggestion that a particular issue is debated in the near future). However, Early Day Motions “carry no entitlement to a House of Commons debate or vote within the scrutiny period.” Likewise, a Member of Parliament might request a half-hour “Adjournment Debate.” However, to get an Adjournment Debate, one must be successful in a ballot or have the subject chosen by the Speaker. Alternatively, Members of Parliament can request time for a debate from the Backbench Business Committee, which decides the debates to schedule or propose an emergency debate.
Clearly then, the patchwork of options that exists to request a debate is far from guaranteed to work. Hence, as noted by the House of Commons Information Office, under the Ponsonby Rule, Parliament “can only overcome the will of the executive to conclude a particular treaty by expressing disapproval and relying on political pressure to change the mind of ministers, or, in the extreme case, by withdrawing its confidence from them.” This probably explains why, to date, “no motion against ratification of a treaty has ever been passed, by either House [or] has even been debated.”
In practice then, to secure a debate on the proposed Chagos Archipelago handover, much will depend on Members of Parliament gathering political support in the House of Commons. Ordinarily, this is a daunting task when there are so many competing objectives and so much background noise in parliament. On the Chagos Archipelago issue however, the stakes might be high enough – and the antipathy of some parliamentarians to the proposed deal might be strong enough – to enable a critical mass of opposition to be leveraged. For example, a number of parliamentarians have already spoken out forcefully against the planned handover in previous debates on the issue, such as Ian Duncan Smith, Tom Tugendhat, Wendy Morton, Robert Jenrick, Mark Francois, Bernard Jenkin and Andrew Rosindell (Conservative) as well as Nigel Farage and Richard Tice (Reform). In parallel, members of the House of Lords “are plotting to force an amendment on [the deal] to require the UK [government] to hold a vote” on the handover, with Lord Bellingham saying “it’s going to be very difficult to override the Lords on this and then it’ll delay things, and I think Trump will then have his say … I’m reasonably optimistic that we can turn the table on this.”
Conclusion
The UK government is currently in the process of ceding sovereignty of the Chagos Archipelago to Mauritius. This is despite the facts that (i) the Archipelago was never part of an independent Mauritius, (ii) the people who lived there were not of Mauritian descent, (iii) the military base on Diego Garcia is critical to Western Security and (iv) there is no judgment of an international court binding the UK to relinquish sovereignty. The Ponsonby Rule requires the government to lay the terms of the proposed treaty before parliament for 21 days with an explanatory note, during which time parliamentarians can seek a debate on the issue and, thereafter, resolve not to ratify the treaty. If this occurs, the government is not permitted to ratify the treaty and the process starts again with another 21 day period. This continues until the treaty is either withdrawn by the government or ratified by the Commons. A point of potential weakness for those in the Commons who oppose the handover is that there is no formal mechanism to trigger a debate. Therefore, in the absence of the government allowing time for a debate itself, political pressure must be brought to bear to force a debate using pre-existing methods. This might be tricky, however it seems that there is enough political inertia to achieve this and, therefore, to save the UK (and Western security more generally) from a self-inflicted injury.
Elliot Winter is a Senior Lecturer (Associate Professor) in international law at Newcastle University in the United Kingdom.
