Scottish Labour members have backed leader Kezia Dugdale's vision for a more federal UK at the party's conference in Perth.
They voted in favour of a motion calling on the UK party to convene a "People's Constitutional Convention", made up of citizens from across the UK, which would then report back before the 2020 general election.
The convention is part of Ms Dugdale's federal approach to the constitution which would see increased powers for Holyrood, Cardiff Bay, Stormont and the English regions.
Read more: SNP has no mandate for second independence referendum, says Labour MP Ian Murray
The Scottish leader's proposals came in response to both Brexit and calls for a second independence referendum, and seek to establish a separate position from both the SNP and the Conservatives.
During a debate on the motion, senior party figures told delegates Labour would oppose another independence ballot and would not share a platform with the Tories in the future, as it had done during the 2014 campaign.
The comments come amid growing speculation Nicola Sturgeon will announce a second referendum in the coming weeks.
Read more: Dugdale describes "personal sacrifice" after double heartbreak
Labour's only Scottish MP Ian Murray said: "I want to make it absolutely clear to both Nicola Sturgeon, and indeed to Ruth Davidson, the SNP has absolutely no mandate for another Scottish independence referendum.
"If they try to push one through, Scottish Labour will oppose it in the Scottish Parliament all the way."
Mr Murray said the Conservatives were to blame for the prospect of another vote dominating the political agenda, branding the party as the "the SNP enablers".
"It is they who are really responsible for this current mess - Nicola Sturgeon's mibbes aye, mibbes naw referendum," he said.
"Thanks to them, the constitution has barely been off the agenda since the early hours of September 19."
Read more: Number of Scottish Labour members and supporters at 20-year high
The MP insisted Ms Dugdale's vision offered a chance to "seize the mantle as the party of federalism".
He added: "The vision before you today is one of hope and optimism.
''It will mean that every part of the UK and every part of Scotland is contributing to our success.
''It will reforge our democracy and our society, and safeguard it for the future."
Scottish Labour deputy leader Alex Rowley said: "We say we will neither support the separatist solution of the SNP nor will we support the status quo of the Tories.
"We will neither cut ourselves off from our neighbours down south under the SNP, nor will we embrace the austerity economics of the Tories.
"We should be clear, and this conference should be clear to its leadership and to the Scottish executive, never will we stand on any platforms with a Tory party which inflicted such misery on the people of Scotland."
There was broad support at the conference for Ms Dugdale's vision but there was caution over her call for a ''new Act of Union''.
Read more: SNP has no mandate for second independence referendum, says Labour MP Ian Murray
Pauline Brown, an activist from Glasgow Kelvin, said: ''We don't want a union of the crowns, we want a union of the people.
''It's not so much constitutional change that we are arguing for, but political change, and that just can't be legislated for.
''It's got to be built from the ground upwards. It's got to be done through hard political struggle.''
An SNP spokesman said Mr Murray's argument that the party had no mandate for a second independence vote was "extraordinarily desperate stuff".
"Just last year, the SNP won a third term in government on a manifesto that specifically said the Scottish Parliament should have the right to hold a referendum if Scotland was taken out of the EU against our will," he said.
"We absolutely, unequivocally have a mandate to pursue this if we consider it in Scotland's best interests. To deny that mandate is to deny reality."
Scottish Conservative leader Ruth Davidson said: "On the day Labour is licking its wounds over its humiliation in the Copeland by-election, the Scottish party decides the way to reconnect with the real lives of ordinary families is a sleep-inducing plan for people's constitutional convention and yet more upheaval to our precious union.
"This is a party that doesn't know when to stop digging. Never has Scottish Labour looked more out of touch or irrelevant."
Scottish Liberal Democrat deputy leader Alistair Carmichael welcomed Labour's "long, slow walk to federalism".
"It's nice to see them join the 21st century for once rather than remaining stuck in 1983," he said.
"We need a thorough refresh of the UK system of governance. No more centralised solutions but devolution of power to communities instead."
Why are you making commenting on The Herald only available to subscribers?
It should have been a safe space for informed debate, somewhere for readers to discuss issues around the biggest stories of the day, but all too often the below the line comments on most websites have become bogged down by off-topic discussions and abuse.
heraldscotland.com is tackling this problem by allowing only subscribers to comment.
We are doing this to improve the experience for our loyal readers and we believe it will reduce the ability of trolls and troublemakers, who occasionally find their way onto our site, to abuse our journalists and readers. We also hope it will help the comments section fulfil its promise as a part of Scotland's conversation with itself.
We are lucky at The Herald. We are read by an informed, educated readership who can add their knowledge and insights to our stories.
That is invaluable.
We are making the subscriber-only change to support our valued readers, who tell us they don't want the site cluttered up with irrelevant comments, untruths and abuse.
In the past, the journalist’s job was to collect and distribute information to the audience. Technology means that readers can shape a discussion. We look forward to hearing from you on heraldscotland.com
Comments & Moderation
Readers’ comments: You are personally liable for the content of any comments you upload to this website, so please act responsibly. We do not pre-moderate or monitor readers’ comments appearing on our websites, but we do post-moderate in response to complaints we receive or otherwise when a potential problem comes to our attention. You can make a complaint by using the ‘report this post’ link . We may then apply our discretion under the user terms to amend or delete comments.
Post moderation is undertaken full-time 9am-6pm on weekdays, and on a part-time basis outwith those hours.
Read the rules hereLast Updated:
Report this comment Cancel