The first ministers of the UK’s nations will meet in Cardiff on Monday.
The momentum for constitutional change is “undeniable”, John Swinney has claimed ahead of meetings with the first ministers of Wales and Northern Ireland.
Mr Swinney will speak to Plaid Cymru leader Rhun ap Iorwerth and Sinn Féin vice president Michelle O’Neill in Cardiff on Monday, as well as a series of engagements with the Welsh Government.
The trio will meet as part of their roles as party leaders rather than first ministers to discuss the future of independence for their respective countries.
The Welsh First Minister’s election in May was the first time all three of the UK’s first minsters supported their countries leaving the union.
Speaking ahead of the meeting, Mr Swinney said: “Every nation across these islands is standing at a moment of incredible constitutional opportunity.
“There is a growing consensus that the Westminster system simply is not fit for purpose and does not work for ordinary people.
“Prime Minister Andy Burnham has accepted that himself – and the people of Scotland, Wales and Northern Ireland have made it clear at the ballot box.
“For the first time ever, Scotland, Wales and Northern Ireland are led by pro-independence first ministers.
“There could be no clearer sign that the status quo is not sustainable – and that Westminster must prepare for a post-UK future.”
The comments come after Prime Minister Andy Burnham this week appeared to suggest there could be another vote on independence should the Scottish people want one.
Downing Street quickly claimed the comments did not represent a shift in position and independence for Scotland remained “off limits”.
But in Scotland, the comment has been seized on as a shift in UK Government policy.
The First Minister added: “Crucially, for the first time since 2014, there is a British Prime Minister who has publicly accepted the democratic principle of self-determination.
“The momentum behind serious constitutional change is undeniable.
“Andy Burnham must now be facing up to the idea that he will go down in history as the final Prime Minister of the United Kingdom.
“Tomorrow in Cardiff, I am looking forward to discussing a better future with partners from across these islands – and that only comes with the fresh start of independence.”
In a letter to the First Minister on Thursday, the Prime Minister said he had been “highlighting that there is no consensus for an independence referendum in Scotland”.
He told Mr Swinney: “As I made clear to you personally when we met recently in Glasgow, independence and a referendum are off limits as it would take our focus away from growing the economy and helping families with the cost of living.”
