The Welsh Government is calling for a major "constitutional reconstruction" of the United Kingdom in order to meet the challenges Brexit poses for the devolved nations and the country as a whole.
First Minister of Wales Carwyn Jones will launch the Welsh Government's policy paper on Brexit and Devolution on Thursday morning, calling for the "inadequate" Joint Ministerial Committee (JMC) to be replaced with a new UK Council of Ministers and for a Convention on the future of the UK.
Mr Jones is expected to tell the Wales Governance Centre event in Cardiff that, while leaving the EU has the potential to destabilise the United Kingdom, it also offers the opportunity for reinvention.
"Leaving the European Union is the biggest challenge facing the United Kingdom, a challenge thrown into even sharper relief by the outcome of the General Election," he will say.
"Decisions taken now will affect Wales for decades to come.
"Our ability to trade, travel, attract investment, determine policies, legislate, support our countryside, invest in our regions - all of these will be influenced by how we leave the EU."
The policy document sets out a blueprint for constitutional renewal and proposes replacing the current JMC with a UK Council of Ministers, served by an independent secretariat and a structured work programme.
The document says: "EU withdrawal raises fundamental questions about the JMC's role and working arrangements.
"In our view, these are inadequate for the new challenges we face.
"The JMC is a consultative body and makes no decisions - it might negatively be characterised as, effectively, a 'talking shop'."
The paper recommends a new council operated along similar lines to, but on a smaller scale than, the EU Council of Ministers, meaning the four administrations would meet regularly in a variety of formats to negotiate common rules and frameworks.
The paper also proposes a Convention on the Future of the United Kingdom, to be chaired by a respected, independent figure.
It suggests the Convention could consider major questions that will face the UK once it is outside the EU and take evidence from all political parties, civil society and all parts of the UK.
The paper concludes: "The Welsh Government appreciates that, for many in the UK, some of the ideas set out in this document may appear challenging.
"Adopting them would amount to a major constitutional reconstruction of the UK, and we do not underestimate this.
"But in our view, the UK's withdrawal from the EU represents an existential challenge to the UK itself.
"As an administration committed to both the Union and devolution, we consider that all options should be on the table, in order to preserve and foster unity for the UK while guaranteeing the diversity of its constituent nations."
Mr Jones will add that the opportunities presented by EU exit must be about the future, not the past.
Of the paper, he will say: "It represents an important step forward in the work which we must undertake together with England, Scotland and Northern Ireland - through discussion, not diktat - to map our collective future."