Cardiff Agreement Memorandum (2026)

Cardiff Agreement Memorandum is an agreement document signed on 14 September 2026 in Cardiff, the capital of Wales, by the leaders of the pro-independence and pro-union parties in Scotland, Wales and Northern Ireland, along with Sinn Féin President Mary Lou McDonald, based on the principle of the right to self-determination.^【1】

The document was signed by John Swinney, leader of the Scottish National Party and First Minister of Scotland, Rhun ap Iorwerth, leader of Plaid Cymru and First Minister of Wales, and Michelle O'Neill, Sinn Féin’s leader in Northern Ireland and Deputy First Minister of Northern Ireland, in their capacity as party leaders, not as official representatives of their respective governments.^【2】 The memorandum calls on the UK government in Westminster to prepare for, plan and facilitate constitutional change but does not set any timetable for independence.^【3】

The meeting took place approximately 48 hours after statements by US President Donald Trump during his visit to Ireland, in which he expressed support for the unification of Northern Ireland and the Republic of Ireland.^【4】

The summit in Cardiff was hosted by First Minister of Wales Rhun ap Iorwerth on Monday 14 September 2026.^【5】 Attendees included Scotland’s First Minister John Swinney, Northern Ireland’s First Minister Michelle O'Neill and Sinn Féin President Mary Lou McDonald.^【6】 The parties attended the meeting not as official representatives of their governments but as leaders of their respective political parties.^【7】 It has been suggested that this situation may have arisen due to O’Neill’s participation in a power-sharing government with the Democratic Unionist Party (DUP) in Northern Ireland.^【8】

The Cardiff agreement coincides with the first period in which all devolved administrations in Scotland, Wales and Northern Ireland are governed by pro-independence parties.^【9】 This situation emerged following Rhun ap Iorwerth’s election as First Minister of Wales after the Senedd (Welsh Parliament) elections in May 2026. In Scotland, the SNP has held the position of First Minister since 2007. In Northern Ireland, Sinn Féin, for the first time, won the most seats in the 2022 elections, narrowly surpassing the Democratic Unionist Party (DUP), and in 2024, Michelle O’Neill officially assumed the role of First Minister of Northern Ireland, becoming the first nationalist politician to do so.^【10】

On Sunday 13 September 2026, the first ministers of the devolved administrations of Scotland, Wales and Northern Ireland made various statements ahead of the planned signing of the memorandum the following day.

First Minister ap Iorwerth, in an interview on BBC’s Sunday with Laura Kuenssberg, said that the meeting would address both common ground and differences. He noted that discussions could also cover the issue of fair funding for Wales and Scotland. Meanwhile, Scottish Education Minister Mairi McAllan, speaking on BBC’s Sunday Show, stated that the option of an independence referendum remains on the agenda.^【11】

Prime Minister John Swinney also argued before the summit that there is momentum toward serious constitutional change. Swinney emphasized that for the first time, Scotland, Wales and Northern Ireland are all led by pro-independence first ministers, calling this a significant indicator of the sustainability of the current political structure. Swinney further argued that Westminster must prepare for a post-United Kingdom future.^【12】

On Saturday 12 September 2026, US President Donald Trump met with Irish Taoiseach Micheál Martin at Farmleigh House in Dublin during his visit to Ireland.

In response to journalists’ questions after the meeting, Trump said he would welcome the unification of Northern Ireland and the Republic of Ireland. He stated that such a unification would happen sooner or later and would be “a wonderful thing,” adding that the United Kingdom would have “something to say” on the matter.

Later, during a speech at the residence of the US Ambassador to Ireland, where he met with business leaders, Trump said that on the issue of Irish unification, there is “no good answer”, but that it would still be “a very nice thing.”^【13】

Trump’s remarks followed comments by UK Prime Minister Andy Burnham weeks earlier, who stated that a referendum on Northern Ireland leaving the United Kingdom was “not on the table”. Gavin Robinson, leader of the Democratic Unionist Party (DUP), Northern Ireland’s largest unionist party, rejected Trump’s prediction. Robinson argued that unification with Ireland would mean “the destruction of our country” and insisted that Northern Ireland’s constitutional future must be determined by the people of Northern Ireland, not by statements from London, Dublin or Washington.

Eamon Hanna, a supporter of Irish unity from the Social Democratic and Labour Party (SDLP) in Belfast, dismissed Trump’s remarks as “mere headline hunting” and said he did not believe Trump was genuinely interested in the issue of a united Ireland.^【14】

During his visit, Trump also met with Irish President Catherine Connolly. In her remarks after the meeting, Connolly said she conveyed to Trump the Irish public’s view that the normalization of war and genocide is unacceptable. Thousands of people participated in a protest demonstration in Dublin during Trump’s visit, carrying flags of Ireland and Palestine. Trump also touched on the issue of sovereignty over the Falkland Islands (Malvinas) during his visit, pointing to potential tensions between the United Kingdom and Argentina on the matter.^【15】

The Cardiff memorandum acknowledges that Scotland, Wales and (Northern) Ireland have distinct histories, identities and political traditions. It emphasizes that each nation has the right to determine its own future through democratic means and in accordance with the will of its people.

The memorandum states that the United Kingdom’s departure from the European Union (Brexit) has harmed economies and restricted opportunities for its peoples. It argues that there can be no clearer signal that the era of Westminster rule is coming to an end; it affirms the right of nations to self-determination. It further stresses that no Westminster government has the right to obstruct democracy or undermine the principle that peoples should determine their own futures.^【16】

Recognizing the parties’ differing constitutional positions, the memorandum states that each nation will determine its own future in its own way and at its own time. It calls on the British government to prepare for, plan and facilitate constitutional change in each jurisdiction.

The agreement text also sets out goals for cooperation in the areas of economy, energy and international collaboration. It rejects the “broken economic model” of Whitehall, calls for the exchange of ideas on economic growth, and proposes the development of energy resources, while affirming that the nations’ futures lie within the European Union.

The text further notes that the political landscape across the islands is changing. It states that for the first time, first ministers advocating independence from the United Kingdom are in office in Scotland, Wales and Northern Ireland; it asserts that there is momentum behind independence movements and a belief in the inevitability of constitutional change. The parties also agreed to strengthen cooperation between their parties and identify areas of joint work.^【17】

The memorandum contains no timetable for independence. Instead, it calls on the British government to prepare for, plan and facilitate constitutional change in each jurisdiction.^【18】

The agreement memorandum was signed on the morning of 14 September 2026 in Cardiff during a formal ceremony. Host ap Iorwerth expressed his delight at welcoming the SNP and Sinn Féin leaders to Wales, stating that cooperation in areas of shared interest could improve the lives of the people they represent.^【19】

At the press conference, ap Iorwerth said the Welsh people had made a decision about their future through the May elections and that this decision was not solely about independence. He emphasized the importance of building the Welsh people’s confidence and demonstrating that change is in their own hands.

ap Iorwerth also stated that a suitable constitutional framework must be established, noting that Wales’s closest allies are first and foremost in Great Britain and Ireland, and then in Europe. He argued that the United Kingdom needs a major reset and a renewal from the ground up, and that the advantages of working together as independent nations are increasingly recognized, while the current status quo is unsustainable.

ap Iorwerth noted that the desire for self-determination is growing and will transform relations between the parties. He stated that England must now choose whether to approach this process positively or to obstruct it.

Scottish First Minister John Swinney referred to the May elections, in which his party became the largest in the Scottish Parliament, saying the result had created a new political reality in the United Kingdom and marked a significant milestone in the constitutional process.

Swinney emphasized that the right to self-determination lies at the heart of the agreement and is an inalienable right of the people. He also argued that Prime Minister Andy Burnham will be the last Prime Minister of the United Kingdom, noting that the Scottish people have chosen the government they want and desire to remain part of the European Union, yet were removed from it against their will.

At the press conference, Swinney affirmed that the Scottish people have the right to determine their own future and argued that Scotland has faced obstruction from the UK government. He stated that the government has repeatedly rejected the SNP’s calls for an independence referendum.

Sinn Féin President Mary Lou McDonald described the signed memorandum as a “historic document”. She noted that as the 30th anniversary of the Good Friday Agreement approaches, Ireland has made significant progress since centuries of occupation and colonial rule.

McDonald stated that Ireland remains divided and affirmed the existence of the right to a referendum and to determine its own future. She declared that they would not accept any British prime minister’s claim that this right is not on the agenda.

McDonald also accused the United States of supporting genocide by selling arms to Israel and called on the US to abandon this stance. She argued that if the US approach to the Irish peace process were applied to Palestine, the situation would be different.

Deputy First Minister of Northern Ireland Michelle O'Neill said that the region is undergoing a major transformation and that this process cannot be halted. O'Neill stated that the Westminster system has not worked in the interests of any of the three nations and that they need the right to determine their own futures.

At the signing ceremony, O'Neill said that US President Trump’s comments on Irish unification demonstrated that the debate on unity is now on the agenda both in Ireland and internationally. She argued that unification is the “real prize,” representing the end of division and a new beginning for a united Ireland.

The UK Prime Minister’s Office, in its statement regarding the message of “self-determination”, affirmed that Prime Minister Andy Burnham is committed to working for all four nations of the United Kingdom and firmly believes in the Union. The office argued that the United Kingdom becomes stronger through unity around shared values and jointly solving problems, rather than through separation.^【20】

Spokesperson Tom Wells emphasized that the Prime Minister is focused on reducing the cost of living for households rather than constitutional debates. The Prime Minister’s Office stated that Burnham’s priority is to reduce pressure on household budgets and enhance economic security, and that he is not focused on constitutional discussions or new referendums.

In response to whether the government sent a representative to the Cardiff meeting, the spokesperson said that Burnham works with the regional first ministers and deputy first ministers of Scotland, Wales and Northern Ireland on the basis of partnership and cooperation.^【21】

Deputy First Minister of Northern Ireland Emma Little-Pengelly (DUP) accused Michelle O’Neill of “arming” her position as First Minister of Northern Ireland by attending the Cardiff meeting and signing the memorandum without seeking any permission or approval from her.

Little-Pengelly argued that O’Neill did not attend the meeting in her capacity as First Minister of Northern Ireland and has no authority to sign any document in that role. She stated that in Northern Ireland, the roles of First Minister and Deputy First Minister are carried out on a basis of shared responsibility.^【22】

In response, O’Neill maintained that she is the First Minister of Northern Ireland and that the events signify a historic period of change in the region.

Irish Taoiseach Micheál Martin stated that addressing the issue of a united Ireland requires serious work rather than simplistic rhetoric or timetables. Martin confirmed that he plans to raise the legacy issue with Burnham during their upcoming meeting.

Martin said the island’s future must be built on three fundamental relationships: Anglo-Irish relations, north-south links, and relations between the two communities in Northern Ireland. He emphasized the need for greater consensus and criticized Sinn Féin for seeking to return to the politics of the 1970s.

McDonald expressed hope that Taoiseach Martin had taken note of the message from the US President and invited him to accelerate preparations for a border poll.

Conor Murphy, Sinn Féin’s leader in the Irish Seanad, said that a new dynamic has emerged in British politics and that this signals a new political landscape. Murphy stated that the meeting between Sinn Féin, the SNP and Plaid Cymru aimed to establish a formal cooperation program among nationalist parties. Murphy argued that Trump’s remarks have strengthened the need for serious preparation for constitutional change, noting that no one wants to enter a process similar to Brexit and that a regular and smooth transition is essential.^【23】

Following the trilateral meeting in Cardiff, Swinney and ap Iorwerth signed on the same afternoon a separate and legally non-binding cooperation agreement between the governments of Wales and Scotland.

The agreement calls for greater justice for Wales and Scotland in areas such as UK funding arrangements and constitutional powers. The two governments also plan to collaborate on various issues, including combating child poverty and maximizing benefits from relations with the European Union.

At the second press conference, Swinney declined to support reform of the Barnett Formula, which determines Welsh funding. He stated that financial arrangements across the United Kingdom vary by nation and that each nation must articulate its own interests and perspectives.

Ap Iorwerth, however, stated that it is important for Wales to be granted at least the same level of flexibility currently enjoyed by Scotland.^【24】

The United Kingdom consists of four constituent countries: England, Wales, Scotland and Northern Ireland. Within these four countries, there are three distinct legal systems. England and Wales share a common legal system, while Scotland has a separate system based on Scots law, and Northern Ireland has a distinct system based on English common law and its own legislation.

In the United Kingdom, powers are shared through a system known as “devolution”, which differs from federal systems such as those in the United States or Germany. Under this system, powers are not constitutionally divided equally between the central government and the four countries.

Although elected institutions have their own legislatures and governments, matters such as defense and foreign relations remain under London’s control. Moreover, none of the countries has the right to unilaterally secede from the United Kingdom.^【25】

In the late 1990s, the United Kingdom enacted legal measures to initiate the devolution process, granting the countries outside England a degree of policy autonomy and self-government through their own parliaments.

Scotland held an independence referendum in 2014, following approval from Westminster; the option of independence was rejected by 55 percent to 45 percent. In Wales, there is currently no legal mechanism allowing the Senedd (Welsh Parliament) to initiate an independence referendum on its own.^【26】

The rules for Northern Ireland are different. According to the 1998 Good Friday Agreement, if the UK Secretary of State for Northern Ireland concludes that a majority of voters in Northern Ireland would support a united Ireland, the UK government is required to call a referendum.

Under the agreement, a referendum on unification can be initiated by the decision of the UK government; for such a constitutional change to occur, it must also be approved by a separate referendum in Ireland.^【27】