The Scottish and Welsh governments have said they cannot recommend that legislative consent is given to the Brexit Repeal Bill as it stands.
In a joint statement, first ministers Nicola Sturgeon and Carwyn Jones described the European Union (Withdrawal) Bill as a “naked power-grab” that undermined the principles of devolution.
UK Scottish Secretary David Mundell countered that the legislation would result in a powers “bonanza” for Holyrood and said he was confident that legislative consent would be forthcoming.
Mr Mundell confirmed the approval of the Scottish Parliament through a legislative consent motion would be required for the Bill, which is designed to transpose EU law into British law so the same rules apply on the day of Brexit as the day before.
In their statement, Ms Sturgeon and Mr Jones said: “This week began with the Prime Minister calling for a constructive and collaborative approach from those outside Whitehall to help get Brexit right.
“Today’s publication of The European Union (Withdrawal) Bill is the first test as to whether the UK Government is serious about such an approach. It is a test it has failed utterly.
“We have repeatedly tried to engage with the UK Government on these matters and have put forward constructive proposals about how we can deliver an outcome which will protect the interests of all the nations in the UK, safeguard our economies and respect devolution.
“Regrettably, the Bill does not do this. Instead, it is a naked power-grab, an attack on the founding principles of devolution and could destabilise our economies.”
The statement continued: “The European Union (Withdrawal) Bill does not return powers from the EU to the devolved administrations, as promised.
“It returns them solely to the UK Government and Parliament, and imposes new restrictions on the Scottish Parliament and National Assembly for Wales.
“On that basis, the Scottish and Welsh governments cannot recommend that legislative consent is given to the Bill as it currently stands.”
The Bill will repeal the European Communities Act 1972, which took Britain into the EU, and bring the body of European law into the constituent legal systems in the UK.
It will allow for changes to existing EU statutes and regulations that will not operate appropriately after Brexit, for example because they reference European entities.
Mr Mundell said that separate legislation would be needed to cover areas such as fishing, farming and immigration and a series of further Bills could also require legislative consent from the devolved administrations.
He insisted that the return of powers and responsibilities currently exercised by the EU to the UK was a “transitional arrangement” that would allow for the further onward devolution of powers while ensuring the consistency of UK-wide frameworks.
In a briefing to journalists, he said: “This is not a power grab, it is a power bonanza for the Scottish Parliament because after this Bill has been implemented the Scottish Parliament will have more powers and responsibilities than it has today and I’m happy to be held to account for that statement once the process has been delivered.
“Needless to say there will be a process row with the Scottish Government because the Scottish Government does process row, that is their speciality.
“We’ve seen process row in relation to the Scotland Bill that followed the Calman Commission, process row on the Scotland Bill, we’ve seen process row on the fiscal framework.
“But all of these things delivered what the UK Government said at the outset that they would do – more powers and responsibilities for the Scottish Parliament and that’s what this Bill will do.”
Mr Mundell said the result of the General Election in Scotland, in which the SNP lost 21 seats, was confirmation that there was “no appetite amongst the public for a separate Scottish arrangement” in relation to Brexit.
“I think it’s clear now that there’s an acceptance in Scotland that we are leaving the EU,” he added.
Mr Mundell continued: “This is a matter which affects the powers and responsibilities of the parliament and ministers, and we will be seeking consent.
“I am optimistic that we will obtain that consent, partly because I was told in relation to the 2012 (Scotland) Bill, in relation to the 2016 (Scotland) Bill, in relation to the fiscal framework, that this consent would not be forthcoming and, ultimately, it was.
“If there was a suggestion that it was not to be forthcoming, there would have to be an explanation to people in Scotland as to why the SNP oppose the bringing into Scots law of European law and why they oppose the Scottish Parliament having additional powers and responsibilities.”
Mr Mundell said further powers would be devolved “as soon as is practical“ but added that some areas would require further discussion over the detail and financial arrangements, drawing the comparison with the complexity of the devolution of welfare powers to Scotland.
Pressed on what powers could come to Holyrood, he said those in areas such as environment, criminal justice, consumer rights and energy “could all in relatively short order come to the Scottish Parliament”.
On separate bills required in areas such as fisheries and agriculture, he added:
“Any piece of legislation which impacts on the powers and responsibilities of the Scottish Parliament requires to go through the Sewel process.
“So, if some of these other pieces of legislation require that in terms of the Sewel Convention, then that’s what the approach will be.”
Scottish Labour leader Kezia Dugdale said: “Labour will seek a clear and binding commitment to repatriate powers in devolved areas to the Scottish Parliament.
“We will insist this must be done in a short, but achievable timeframe.
“If there is not a clear presumption of devolution, as well as the other demands set out by Keir Starmer, Labour has been clear that our MPs will not support this Bill in the Commons.
“It is my firm belief that we must not lose sight of the potential to strengthen the powers of the Scottish Parliament, the Welsh and Northern Irish assemblies or the regions of England as part of a more federal United Kingdom.”