The Conservatives' "English votes for English laws" plan would create a "constitutional mess", the deputy leader of Northern Ireland's Democratic Unionist Party (DUP) has said.
Nigel Dodds said he felt the Tories' manifesto, launched last week by David Cameron and William Hague, was "fuelling nationalist paranoia".
He also called for tactical voting by pro-union voters in Scotland, urging them to vote for the "unionist candidate best placed to win their seat", regardless of which party they represent.
Writing in The Guardian, Mr Dodds said of the SNP: “In a hung parliament, regardless of ideology, these are not the politicians set on stability and good government.
“Yet whatever those of us who believe in the continuation of the UK as a pluralist, multi-national state might think, we mustn’t allow ourselves to be provoked into behaving the same way. And this is where the campaign south of the border has so alarmed me.”
'Constitutional mess'
Referring to the Tories' "English votes for English laws" plan as "'Evel", Mr Dodds said: "It's not just a flawed political tactic, it's also a constitutional mess. The Commons can't be used as a part-time English assembly. It's the union parliament and abusing it in this way wouldn't and couldn't answer the very real needs England has.
“For far too long now we have blundered into unthought-out, one-sided constitutional change. This fatal habit has to end. Evel, unfortunately, would simply be more of the same.”
Launching the proposal last week, Mr Cameron said it was “simply unfair” that Scottish MPs would soon be able vote on English income tax, when English MPs could not reciprocate due to devolution.
"English votes for English laws is not about fragmenting the UK," Mr Cameron said. "It's not about division and difference and pulling apart, it is about making our United Kingdom stronger.
“Because if you have basic constitutional unfairness like we’ve had, if you have the people in one part of the UK feeling like they are getting a raw deal, then resentment festers and that undermines the bonds and the fellow-feeling that are the basis of the United Kingdom.”
PA