THE Tories’ plans to introduce English votes for English laws (Evel) descended even further in farce yesterday, as Scottish MPs have criticised a senior

Tory MP who implied they could be blocked from voting on Heathrow’s third runway despite the huge impact it would have on Scotland.

Speaking to the BBC’s Sunday Politics programme, MP Iain Stewart, David Mundell’s parliamentary aide, said Evel would mean any bill to set up a new runway would have go through “an additional stage in the legislative process” that would ultimately stop it passing unless approved by English MPs.

The SNP have been courted by Heathrow Airport chiefs, who know David Cameron may have difficulty getting a third runway past a rebellion of backbench MPs and Cabinet members.

The airport was a visible presence at the SNP conference in Aberdeen this weekend, hosting fringe meetings and sponsoring a busy lounge at the entrance to the conference centre. Its marketing slogan was: “Let Scotland fly”.

The party have previously suggested more connectivity to Scotland and cheaper fares for Scots flyers could help secure their backing for the new runway. Over the last 10 years, daily services between Heathrow and Scotland have dropped from 50 to 26. The SNP have made Heathrow aware that there needs to be a firm, long-term commitment to keeping existing routes and opening new ones.

Former first minister Alex Salmond last week suggested the Barnett consequentials of the project could be worth £500 million to the Scottish Government.

Cameron is expected to make a decision on the third runway at Heathrow before Christmas.

Zac Goldsmith, the MP for Richmond Park who is the Tory candidate for Mayor of London and a firm opponent of the third runway, said the decision did not affect Scotland and SNP MPs would be “crossing the line in terms of democracy” if a deal was struck.

Many London MPs are opposed to the noise and air pollution that would be caused by the new runway, while others are concerned about the environmental damage.

Drew Hendry, the SNP's transport spokesman, said it would be “absurd” to make it an English-only issue.

“Heathrow is constantly being promoted by the UK Government as a national infrastructure project – with huge ramifications on air connectivity for Scotland, Wales, Northern Ireland and the regions of England” he said.

“It will involve a minimum of £5 billion of public spending – and it would be completely absurd and totally unacceptable to assign it as an English-only issue.”

The row over Heathrow came as the government’s Evel proposals were criticised for being “over engineered and potentially burdensome” in a report published today by the House of Commons Procedure Committee.

Angus Robertson MP, the SNP’s leader in Westminster, said the report showed the “utter confusion and total inadequacy” of the government’s proposals. “The Tories have got themselves into a first-class muddle and are trying to force this through," he said.

“English votes for English laws puts forward an absurd solution to the UK’s current constitutional inequalities and it is clear that the proposals need to go right back to the drawing board.”

Labour’s shadow Scottish secretary Ian Murray said the report showed what an “incomprehensible mess” Evel was.

“David Cameron’s proposals will weaken our democracy, weaken Scotland’s voice in parliament and for the first time create two classes of MPs. It could lead to the perverse situation where some unelected members of the House of Lords will be more powerful than elected MPs.”