A group of high-profile Labour politicians have banded together to campaign for "urgent" reform of the UK's democracy.
Former prime minister Gordon Brown, Welsh First Minister Mark Drakeford and Greater Manchester Mayor Andy Burnham are among those who have joined the Alliance for Radical Democratic Change.
They will launch the push at an event in Edinburgh this evening, alongside West Yorkshire Mayor Tracy Brabin and Scottish Labour leader Anas Sarwar - where they will call on political leaders from other parties to back their goal.
It comes six months after a report released by Mr Brown on the future of the UK recommended the abolition of the House of Lords and deeper devolution to the cities and regions.
In a joint mission statement, the group said: "There is a UK-wide demand for change.
"We recognise the urgent need for working together - locally, regionally and nationally across the UK - to reform our constitution so we can deal with the current economic and social challenges faced in every area of our country.
"To that effect we are creating the Alliance for Radical Democratic Change to implement wide-ranging proposals for the reform of the UK."
The reforms the group want to see include:
To end the centralisation of power in Whitehall and Westminster
To devolve effective economic and social powers to the regions and nations
To make cities and regions centres of initiative for full employment and good jobs
To ensure co-ordination between all levels of government to "achieve a fairer, greener and wealthier Britain"
Speaking ahead of the event, Mr Drakeford said: "We need a new strengthened union which guarantees that no-one will find themselves unable to eat or relying on a food bank; facing old age or illness at the margins of society.
"A union which offers strong devolution for all parts of the UK; a union where all four nations are treated as equals."
Mr Burnham said: "Just like Scotland, Wales and Northern Ireland, the north of England has suffered from an over-concentration of political and economic power in the South East of the UK.
"This is changing with the devolution of power out of Westminster, but in our experience it works best when it goes deep.
"Places in all parts of the UK should have the ability to build a better future from the bottom up and collaborate with neighbours."
Writing earlier this week in the Scotsman, Mr Brown added: "We need to begin the major reform of Britain so that the way we run ourselves is more democratic, less corrupt, and more responsive to the wishes of people from across our diverse nation.
"We desperately need the new modern institutions, reflective of the values we hold, which ensure power is shared across Britain, not handed down from on high. We need Westminster and Whitehall to show more respect to people who, as surveys shows, feel 'neglected', 'forgotten', 'ignored' and patronised as second-class citizens.
"A new alliance of people from across Scotland, England and Wales demanding change shows we are moving closer together, not further apart."
The event has been organised by Mr Brown and the group will launch in conjunction with his think tank Our Scottish Future.
It comes as Scotland's independence minister has urged Mr Brown to apologise to the people of Scotland, claiming the promises he made alongside then prime minister David Cameron and deputy PM Nick Clegg in the lead up to the 2014 referendum have not been kept.
In a statement released ahead of the Edinburgh rally, Jamie Hepburn said Mr Brown had "made promises that would have made even snake-oil salesmen blush".
He said Mr Brown "could not have been clearer that if people in Scotland voted against independence, in his own words, that 'we're going to be, within a year or two, as close to a federal state as you can be'."
The SNP MSP said since the independence vote in 2014, Scotland has been "dragged out of the EU against our will" and has seen the powers of the Scottish parliament come "under attack like never before".