This briefing has been prepared in advance of a House of Lords debate on 16 December 2021 on Bosnia-Herzegovina and upholding the Dayton agreement. The briefing provides information on recent developments in Bosnia-Herzegovina, focusing on warning from the High Representative for Bosnia and Herzegovina that the Serb member of Bosnia-Herzegovina presidency, Milorad Dodik, was pursuing tacitly secessionist policies. It also summarises the international reaction to these developments.
Bosnia and Herzegovina and the Dayton agreement (275 KB , PDF)
On 16 December 2021, the House of Lords is due to debate a motion moved by Lord Bourne of Aberystwyth (Conservative) that “this House takes note of the importance of the constitutional integrity of Bosnia-Herzegovina, and of upholding the Dayton agreement”.
In 1995, representatives of Bosnia and Herzegovina, Croatia, and Yugoslavia (then comprising Serbia and Montenegro) signed a peace agreement known as the Dayton agreement. This established Bosnia and Herzegovina (BiH) as a single state comprised of two entities. These two entities are the Federation of Bosnia and Herzegovina, principally comprised of Bosnia Muslim and Croat-majority areas, and Republika Srpska, principally comprised of Serb majority areas. The three-person presidency of BiH was also established. Each of these presidents represent one of the three main ethnic and religious groups in Bosnia and Herzegovina: the Bosniaks, Croats and Serbs.
Responsibility for the implementation of the military aspects of the Dayton agreement was handed to NATO. In 2004, NATO forces handed over responsibility for supporting the stability of BiH to an EU‑led force. The Dayton agreement gave responsibility for implementing its civilian aspects to a specially appointed high representative for BiH.
In October 2021, the Serb member of the BiH presidency, Milorad Dodik, said Republika Srpska would withdraw from BiH state institutions including the army, judiciary and the country’s tax system. In November 2021, the current high representative, Christian Schmidt, published a report criticising Dodik. He accused him of pursuing secessionist policies for Republika Srpska and seeking to undermine the Dayton agreement. Schmidt said BiH now faced its gravest existential threat since the end of the Bosnian War in 1995.
Following the publication of the high representative’s report, the UK Government has stated its support for the sovereignty and territorial integrity of BiH. It has also said it supports the maintenance of the settlement established by the Dayton agreement and the work of the high representative. Similar statements have been made by the US Government, the EU and NATO.
Members of both the House of Commons and the House of Lords have raised concerns about the situation in BiH. During a debate in the House of Commons on 2 December 2021, MPs criticised the threats by the Bosnian Serb leadership to withdraw from state institutions. Members of both Houses have also criticised Russia, accusing its Government of seeking to undermine peace and stability in the western Balkans and block attempts by BiH to join NATO and the EU.
Bosnia and Herzegovina and the Dayton agreement (275 KB , PDF)
The ‘Strategic defence review 2025’ (SDR) was published on 2 June 2025. Contending that the UK faces a generational defence and security challenge, the SDR makes 62 recommendations across the armed forces and wider society to meet this threat. The government has pledged to implement all those recommendations. However, critics question where the resources to meet the requirements of the SDR will come from, despite government pledges to raise defence spending levels.
The Chagos Archipelago has been the subject of a long-standing dispute over its sovereignty between the UK and Mauritius. Having been retained by the UK since 1965, the largest island, Diego Garcia, later became the site of a joint UK-US military base. In May 2025, the UK reached an agreement to transfer sovereignty of the islands back to Mauritius, while maintaining an initial 99-year lease of Diego Garcia. The agreement also includes security and financial provisions.
In January 2025 the House of Lords Constitution Committee published a report on the responsibility of the government (the executive) to oversee the constitution. It concluded that the UK’s constitutional arrangements would benefit from several improved safeguards, such as the appointment of a senior minister to advise on constitutional matters and for advisory bodies to be put on a statutory footing.
