DAVID Mundell has described a No Deal Brexit as a “fundamental threat” to the Union and claimed it is now Nicola Sturgeon’s preferred outcome.

The Scottish Secretary said that if the UK suffered a chaotic departure from the EU it would be a recruiting sergeant for the Independence movement.

The comments show the UK government has now dumped Theresa May’s previous mantra that ‘No Deal is better than a bad deal’ in an all-out effort to secure backing for her plans.

The Scottish Secretary was savaged by other parties for backing the PM’s draft withdrawal agreement, despite effectively admitting it would harm Scotland.

The SNP said that for Mr Mundell to advocate a course of action that was against Scotland’s interest was “untenable” and he should resign.

Scottish Tory MP Ross Thomson last week urged Mr Mundell to follow other ministers out the Cabinet, telling him "no unionist" could support the proposals on the Irish backstop.

Under the plan, the UK could remain in a customs union with the EU until Brussels lets it out.

Speaking on BBC Radio Scotland, Mr Mundell admitted the deal was flawed but said it was a choice between that and a “catastrophic” No Deal.

He said: “I'm supporting the deal because I believe a no-deal outcome would be catastrophic for Scotland.

"I believe it would be a fundamental threat to the continuation of the United Kingdom and therefore in the round you have to weigh up all the issues.

"These are difficult and complex judgments but I'm not prepared to countenance a no deal outcome for Scotland.

"Everyone is clear it's not a perfect deal.

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Mr Mundell was pressed on why he described former Brexit Secretary Dominic Raab as a “carpetbagger” and claimed he had quit the cabinet to further this career.

At the weekend, Mr Raab claimed he was puzzled by the attack, and said Mr Mundell had also expressed reservations about the PM’s plan.

Mr Mundell said he had "different principles" to Mr Raab, and said he backed the deal because, overall, it was better than a No Deal that would fracture the Union.

He said: "That's why Nicola Sturgeon is so keen on it.

“That's why she's mandating her MPs to vote for a no deal Brexit, because she understands that the chaos and disruption that a no deal Brexit would bring would be the best recruiting base for her independence referendum."

Ms Sturgeon has always said the choice between the PM’s deal and No Deal is a false one, and that voting down the former would not inevitably lead to the latter.

SNP MSP Tom Arthur said Mr Mundell became more ridiculous each day and was clinging to office "without a shred of principle or credibility".

He said: “It seems there is literally nothing that can happen that would lead David Mundell to put Scotland’s interests before the Tory party’s interests.

“He is quite clearly the cabinet’s man in Scotland rather than Scotland’s man in the cabinet – and his position is now utterly untenable."

Scottish LibDem leader Willie Rennie said: "The Scottish Secretary can't bring himself to say the Prime Minister's deal will make life better for people in Scotland - because it won't.

"Nobody is fooled by David Mundell's unconvincing claim that this is the only way forward.

"The Brexit decision needs to go back to the people."

Shadow Scottish Secretary Lesley Laird said: “Theresa May once believed that no deal was better than a bad deal. Now David Mundell is saying the exact opposite, yet sees no conflict with his position in Cabinet.

“To back this bad deal as the only alternative to a no deal Brexit is to accept a false choice.

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