SNP constitution secretary Michael Russell claims Holyrood is suffering a slow demise as powers are “unpicked” by the UK Government.
Mr Russell’s comments sparked another major row between governments as parties get on an election footing.
The claim also comes as polls suggest the SNP might not get a majority in May while the future of the UK appears finely balanced.
A UK Government official rejected Mr Russell’s accusations and claimed the public want to see administrations “working together”.
Mr Russell revived the “power grab” argument in a report published by the Scottish Government on Monday raking over developments since the Brexit vote.
He said: “Since the Brexit vote there has been a systematic attack on the Scottish Parliament’s powers, fundamentally undermining devolution.
“Bit by bit, the settlement that secured 74% support in the 1997 devolution referendum is being unpicked under the cover of Brexit and without the consent of Scottish people.
“This is not a big bang abolition – it is instead the slow demise of devolution in the hope that no-one will notice.”
Mr Russell focused on the Internal Market Act, branded by the SNP as a “power grab”, as well as the so-called levelling up and shared prosperity funds.
The approach would allow the UK Government to directly fund devolved areas bypassing Holyrood, the SNP claim. Devolved areas caught up in the row include agriculture, health, and food and drink.
UK is ‘most successful’ political union
The report claims the views of devolved parliaments have been overlooked. The Scottish, Welsh and Northern Irish legislatures all voted to withhold consent to the final Brexit deal in early 2020 – but the deal was approved, anyway.
A UK Government spokesperson said: “Now more than ever, people in Scotland want to see the UK Government and devolved administration working together to protect lives and livelihoods.
“The United Kingdom is the most successful political and economic union the world has ever seen, and this pandemic and our collective response, from the furlough scheme to vaccine procurement and the backing of our military personnel, has shown that we are at our strongest when we work together towards a common goal.
“The Prime Minister remains fully committed to strengthening and levelling up all parts of the country by empowering local communities across the United Kingdom.”