Labour and the SNP accused the Conservative Government of abandoning the Union and attempted gerrymandering after ministers unveiled beefed-up plans to restrict Scottish MPs voting rights.
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The row erupted after Chris Grayling, the leader of the House of Commons, unveiled new fast-track proposals for 'English votes on English laws' (evel).
The plans, which include a new right of veto and the need for an unprecedented 'double majority" of both English and UK MPs on certain votes, would "right a wrong" he said.
But opponents denounced the plans as "and assault on the rights of MPs" that would create a tier of "second-class" politicians in the Commons.
First Minister Nicola Sturgeon also predicted the changes would make Scottish independence more likely.
"There is no question that the great disrespect shown to Scotland in these proposals is likely to have more people asking whether Westminster is capable of representing Scotland's interests at all," she said.
Conservative Scottish Secretary David Mundell rejected the warnings, predicting that evel would "make the Union stronger".
The proposals have been significantly strengthened since similar plans were set out by former Tory leader William Hague earlier this year.
They would allow English MPs (or occasionally English and Welsh MPs) a veto over laws affecting only England.
Lords amendments sent back to the Commons for consent would also need a "double majority" - of both English and UK MPs.
That system would also see the use of tablet computers to count Commons votes for the first time - expected to lead to accusations of a slippery slope towards electronic voting, which some MPs oppose.
There would be English MP votes on clauses as well as on entire Bills, while Mr Grayling said a "decisive vote" on tax measures would be given to English MPs after the devolution of income tax and other powers to Scotland.
The Tories included a pledge to introduce an English rate of income tax in their election manifesto, prompting accusations of betrayal from then Sottish Labour leader Jim Murphy.
Mr Grayling told MPs that English voters had for too long felt they had had a bad deal from devolution.
The plans would "answer the West Lothian question", he told MPs.
The issue was first raised by then Labour MP for the area Tam Dalyell, who wonder why devolution would leave him able to vote on issues like health in Blackburn, Lancashire, and not Blackburn, West Lothian.
But the government faced accusations of attempted gerrymandering, by trying to tie the hands of any future Labour Prime Minister who did not have a majority of among English MPs.
Such a scenario could leave a Labour government struggling to pass legislation on taxes, schools and hospitals south of the border, without Tory backing.
Government sources admitted that the changes would create "high stakes".
They pointed to the example of schools policy, saying if future Labour governments wanted to scrap the Conservatives controversial academies scheme they would have to win over a majority of English MPs, most of whom could be Conservative.
Critics of the new scheme also warned that the reforms would see the Speaker, John Bercow, effectively decide what counts as 'England-only' legislation.
They argue that the size of England within the UK means that many apparently 'England only' measures have significant effects north of the border.
Government sources indicated that they were confident they would win a Commons vote on the plans, scheduled for July 15.
But opposition parties predicted the result could be "tight".
Labour, the Lib Dems, the SNP and the DUP are all expected to vote against the move.
Former Scottish secretary Alistair Carmichael accused the government of "an outrage" by trying to push through such a major constitutional change with a 90 minute debate on changes to Commons procedures.
He has written to the Speaker seeking to set aside Commons business next Tuesday for a debate on how ministers are attempting to introduce evel.
SNP MP Pete Wishart accused the Conservatives of hastening the speed of Scottish independence.
"I almost congratulate them for the almost ham-fisted approach that they're having to Scottish issues because all this is going to do is make the whole movement toward independence even more irresistible," he toild Mr Grayling as he denounced the plans as "unworkable garbage".
Labour's shadow Scottish Secretary Ian Murray said the Conservatives had "given up on the Union."
Labour former minister Fiona Mactaggart described the proposals as a "knife in the heart of the Union".
House of Commons Library research suggests evel would have affected just 0.7 per cent of votes since 2015.
Supporters of evel, however, point to the controversial 2004 vote to increase tuition fees in England, passed with the backing of Scottish MPs.
Conservative Tom Pursglove (Corby) said it was "simply unpalatable" to devolve more power to Scotland without addressing the West Lothian Question.
Daniel Gover, a researcher at Queen Mary University of London, said that one challenge would be that "decisions that appear to affect only one part of the UK can in fact have 'spillover' effects into other parts. The most high-profile example relates to funding arrangements, given that spending in Scotland, Wales and Northern Ireland is adjusted by reference to spending in England through the Barnett formula"