The leaders of Sinn Féin, the Scottish National Party and Plaid Cymru in Wales have declared “Westminster’s time is coming to an end” in a joint agreement aimed at putting pressure on Downing Street to hold referendums on independence.

The first ministers of the UK’s three devolved nations – SNP leader John Swinney, Plaid Cymru leader Rhun ap Iorwerth and Sinn Féin vice president Michelle O’Neill, the First Minister of Northern Ireland – signed the memorandum of understanding during a meeting in Cardiff on Monday morning.

Along with Sinn Féin president Mary Lou McDonald, the leaders called on the government to “prepare for, plan and facilitate constitutional change”.

The group, which met in their capacity as party leaders – rather than as officials in their respective governments – also stated their ambitions for partnership around the economy, energy and international co-operation.

The agreement says: “The political landscape across these islands is changing.

“For the first time ever, people across these islands have first ministers in Scotland, in Wales and in the North of Ireland who are all committed to independence from the United Kingdom.

“For people watching across these islands – for people watching around the world – there could be no clearer sign that Westminster’s time is coming to an end.

“We believe there is a better way: nations working together as equals, sharing ideas and expertise, and building relationships based on mutual respect and common interests.

“Momentum is behind our movements; we believe that constitutional change is coming.

“We therefore commit to strengthening co-operation between our parties and identifying practical areas where working together can make a real difference.”

The agreement sets out plans to “reject Whitehall’s broken economic model” and share ideas on economic growth, expand energy resources, and states “the future of our nations belongs in the European Union”.

The leaders add: “Our nations have the right to self-determination. No Westminster government has the right to block democracy or undermine the principle that our people will decide their own future.

“We recognise that our parties have different constitutional positions and that each nation will determine its own future in its own way and in its own time.

“We call for the British Government to prepare for, plan and facilitate constitutional change in each jurisdiction.”

Leaders of Northern Ireland, Scotland and Wales to sign memorandum on independence on Monday

Earlier, McDonald said Donald Trump’s comments on Irish unity have increased pressure on the Taoiseach to start planning for a border poll.

During his visit to Ireland at the weekend, the president of the United States made a number of comments supporting Irish unity, which he said would be a “great thing” that “should happen.”

The Sinn Féin leader said she was not surprised at Trump’s comments, as the United States had been a partner in building the peace process for decades.

“It’s certainly the first time that it’s been expressed so explicitly, and that’s obviously in the style of the serving president. But people just need to remember that this is a long-standing effort over successive administrations and on a bipartisan basis for the United States to back Ireland,” she told RTÉ Radio 1’s David McCullagh show.

McDonald said she welcomed Trump’s comments, and hoped they would “clarify” matters for the Government and the Taoiseach.

“The Tánaiste has a more advanced position on these matters, and Micheál Martin, quite frankly, needs to catch up because this is a serious matter,” she said.

“We need to get this right. We need to be orderly, prepared. This transition from a partition to United Ireland has to be absolutely peaceful. It has to be democratic, it has to include all shades of opinion, all across the spectrum, right across our island, including voices from unionism and loyalism. And that’s not just going to happen by chance. The Government in Dublin needs to be very front-footed from here on in, in shaping and clearing the space for that democratic conversation.”

Northern Ireland’s Deputy First Minister Emma Little-Pengelly of the DUP previously said O’Neill had “not sought any agreement or permission from me to travel, attend or sign anything as First Minister”.

McDonald said O’Neill “doesn’t need the permission of anybody to travel here”. McDonald said the memorandum of understanding was being signed between Sinn Féin, the SNP and Plaid Cymru.

“And they are the three political parties that have produced and provided the first ministers in Wales, in Scotland, and in the north, respectively.” – Additional reporting PA

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