Scottish Labour leader Richard Leonard has told MPs he does not accept the current Brexit devolution deal.
The deal on the table has been rejected by the SNP-led administration in Scotland but accepted by the Labour-led Welsh Government.
There have been months of negotiations over clause 11 of the EU Withdrawal Deal, which centres on the repatriation of powers, including fishing and farming, from Brussels to the devolved administrations.
Now Mr Leonard has drawn a line in the sand between the Labour group in Scotland and the party in Wales and said he would be speaking to leader Jeremy Corbyn this week about the proposals.
MSPs were giving evidence to Westminster’s public administration and constitutional affairs committee yesterday.
“We wouldn’t accept it,” he said. “There still some aspects of this that need to be addressed.
“This still fails to recognise properly the 1998 Devolution Act and the default position of powers residing with the Scottish Parliament and not the UK Parliament.
“I haven’t spoken to the Labour party in London, but I will be doing so over the course of the next two days.”
Green co-leader Patrick Harvie also insisted that the deal was not up to scratch adding that it was “a source of great frustration” because there was a lot of common ground.
He said: “This notion of a common framework is actually achievable without extra restriction on the legislative ability and freedom of the Scottish Parliament and the Scottish Government.
“But it can only happen in a respectful way when either side of that relationship threatens a backstop.
“UK-wide frameworks will be best achieved in a spirit of respect and cooperation, not in a spirit of intimidation and coercion.”
Scottish Liberal Democrat leader Willie Rennie added “further compromise and agreement is required”.
But Scottish Conservative constitutional spokesman Adam Tomkins said the Scottish Government’s position was not in the spirit of devolution.
He said: “The Scottish Acts are not full of veto powers – they are full of requirements on ministers to cooperate with each other and that, in my, view is what clause 11 does.”
Scotland’s Brexit Minister Michael Russell said he believed the current deal would see Holyrood “very substantially overruled for a substantial period of time” by Westminster.
He said: “What I think it does reflect, regrettably, is the trust on which the relationship has to be based is at a pretty low ebb, probably the lowest ebb I have experienced.”