DAVID Cameron is “systematically undermining and destroying” the Union with English votes for English laws, former Scottish Secretary Alistair Carmichael warned yesterday.

Carmichael told the Scottish LibDem conference that Evel had been “bulldozed” through parliament in an “act of wanton constitutional vandalism” on Thursday.

The change, which gives English MPs a veto over English-only laws, was achieved by adding 17 pages to the Commons rule book instead of through substantive legislation.

Evel’s cross-party opponents say it ends the centuries old convention that all MPs are equal.

Its backers say it gives English MPs more say over English matters in light of devolution to Scotland, Wales and Northern Ireland.

Carmichael said Evel had “politicised” the Commons speaker, who must rule which laws are English-only, and “created two classes of MP”, adding: “It’s a disgrace.”

He said Evel would “foster a sense of grievance in Scotland, Wales and Northern Ireland. For those of us who want to see the United Kingdom continue it makes it all much more difficult.

“It is extremely ironic that in Scotland we have [Tory leader] Ruth Davidson telling you that she and she alone can save the Union when in London David Cameron, a victim of his own right wing, is systematically undermining it and destroying it. The answer is a federal structure for the whole of the UK and we are the people that must lead this fight.”

The Orkney and Shetland MP, who faces a court hearing next month over the phoney Frenchgate affair during the election, was speaking in a debate on a new federal treaty of union.

Earlier, delegates rejected a proposal to go into the Holyrood election advocating an extra penny on income tax to raise more funds for health.

Paisley councillor Eileen McCartin said the idea would be “bold”, honest with voters, and strengthen the party’s anti-austerity credentials.

She warned many voters no longer know what the LibDems stood for after five years of “compromise and pragmatic politics” in Coalition with the Tories at Westminster.

“We need a clear policy. What we don’t need is a mibbes aye, mibbes naw policy,” she said.

However, activists backed Edinburgh Western candidate Alex Cole-Hamilton's amendment to water down the plan, making extra taxes a last resort not the first option.

Delegates also called on the SNP Government to end its blanket ban on growing genetically modified crops in Scotland, calling for a scientific, evidence-based approach instead.