THERESA May is risking electoral Armageddon in Scotland similar to the Conservatives’ 1997 wipeout as a consequence of “disrespecting devolution,” the SNP leadership has warned.

Ian Blackford, who leads the Nationalists at Westminster, suggested the Prime Minister and her party would pay a heavy political price for continuing with the EU Withdrawal Bill in the face of widespread opposition in the Scottish Parliament.

“I would say to the Conservatives: be very careful,” declared the Highland MP.

“We’ve been here before when the people of Scotland did reflect on a government[which began] under Thatcher that was perceived as not acting in the interests of the people of Scotland and the Conservatives paid a price.

“The Conservatives have recovered in the polls with the 13 seats in the election last year but I would say to them: be careful…When the Government in London is disrespecting devolution, I hope the people of Scotland would reflect on what they are doing. The Tories were wiped out in Scotland in 1997 because of the perception people had on their behaviour.”

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Asked if Mrs May’s party in Scotland could, therefore, be facing an electoral Armageddon, Mr Blackford replied that its undermining of the devolution settlement was “going to be in the public consciousness” and the PM and her colleagues needed to reflect on that.

In 1997, the Tory Government of John Major lost all 11 seats it held in Scotland during the New Labour landslide of Tony Blair.

On Tuesday, Holyrood decided by 93 votes to 30 to reject the UK Government’s changes to the Brexit bill and, for the first time, withheld its consent to what the majority regarded as a “power-grab” by Whitehall. The Scottish Conservatives were the only party to back the legislation.

Earlier during Prime Minister’s Questions, Mrs May defended her decision to plough on with the Brexit bill despite the opposition from Edinburgh.

She insisted the legislation “set out a mechanism that respects devolution and lets us maintain the integrity of our own common market as we work out the long-term solutions”.

“That,” she declared, “is a reasonable and sensible way forward. The Welsh Government and now the Welsh Assembly, including Labour and Liberal Democrat Members of the Welsh Assembly, agree with that. It is right that we go ahead with measures that not only respect devolution but ensure we maintain the integrity of our common market.”

But Mr Blackford called on the PM to respect the vote of MSPs.

“It is very simple: the Tories are seeking to veto the democratic wishes of the Scottish Parliament. This is absolutely unprecedented. If this Government force through the legislation without the consent of the Scottish Parliament, she will be doing so in the full knowledge that they are breaking the 20-year-old devolution settlement. Will the Prime Minister reassure the House that the Withdrawal Bill will not go through without the consent of the Scottish Parliament?” he asked.

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But Mrs May refused to give such an assurance, saying: “Of course, we are disappointed that the Scottish Parliament has not granted its consent; we have been working hard in recent months to find a way through on this issue and the effort put into this has been shown by the fact that the Welsh Government and Assembly have given their consent to this Bill.”

She told Mr Blackford: “We want to ensure the integrity of the United Kingdom’s common market, and when he talks about the democratic will he might wish to recall the fact that it was the democratic will of the Scottish people to remain in the United Kingdom.”

It is now expected that, in early June when the Withdrawal Bill returns to the Commons, MPs will have a further chance to debate the Government’s amended Scottish clause as well as vote on the 15 amendments on which the Lords defeated the Tory administration.

Yesterday during the final stage of the bill in the Lords, the Third Reading, peers voted by 294 to 244 to defeat the Government and support the maintenance of EU environmental principles and standards post-Brexit.

Tensions broke out with an extraordinary attack by Tory peer Lord Framlingham, the former deputy Commons Speaker, who accused his colleagues of trying to wreck the bill.

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To cries of "shame" and "rubbish" from other peers, he said scrutiny of the legislation had seen the Lords "at its worst" as peers had "used and abused" the parliamentary system to try to "further their own ends and stop us leaving the EU".

But Tory colleague Lord Cormack interjected, telling him: "If anybody is doing damage to the reputation of this House, it is you."