The First Ministers of Wales, Scotland, and Northern Ireland are scheduled to meet in Cardiff on Monday to discuss enhanced cooperation, including constitutional matters. This marks the first in-person gathering of the three leaders since Rhun ap Iorwerth of Plaid Cymru assumed office in May.

Ap Iorwerth will host John Swinney, the leader of the Scottish National Party (SNP), and Michelle O'Neill of Sinn Féin. Sinn Féin President Mary Lou McDonald is also expected to attend the meeting. Later in the afternoon, ap Iorwerth and Swinney are slated to sign an agreement detailing future collaboration on areas of mutual interest.

This meeting occurs at a time when all three devolved administrations have leaders who advocate for leaving the United Kingdom. A spokesperson for Plaid Cymru highlighted the meeting as an opportunity for the leaders to "come together and talk about how we can work more closely on the issues that matter to people across our nations." The spokesperson added that following recent elections and a shifting political landscape, there is a strong rationale for practical cooperation on energy, the economy, Europe, and broader constitutional questions, including the right to self-determination.

John Swinney expressed that there is "undeniable" momentum behind constitutional change, stating that "every nation across these islands is standing at a moment of incredible constitutional opportunity." He also commented that "the Westminster system simply is not fit for purpose and does not work for ordinary people," a sentiment he believes is shared by the public and acknowledged by figures such as Prime Minister Andy Burnham.

The discussions follow recent remarks by Prime Minister Andy Burnham during Prime Minister's Questions regarding the possibility of a second Scottish independence referendum. Burnham drew a parallel between the conditions for a Scottish referendum and a border poll in Northern Ireland, suggesting that a referendum could be considered if there was clear public support and a changed public opinion.

However, Burnham later clarified that another Scottish referendum remains "off limits." In 2014, Scotland held an independence referendum where 55% of voters chose to remain part of the UK, with 45% voting in favor of independence.