DAVID Mundell has issued a barely-disguised threat to quit the cabinet over a no-deal Brexit, saying he would do “whatever I deem necessary” to stop it.

The Scottish Secretary said he would not leave the Conservative party, but twice refused to say whether he would resign from the government.

He said a no-deal would play into the hands of Nicola Sturgeon and the SNP by damaging the Union and boosting calls for Scottish independence.

"I will do everything I can, and whatever I deem necessary, to prevent a no deal Brexit coming about,” he said when asked about his future in the cabinet.

Mr Mundell’s comments, at an event in Edinburgh marking 20 years of devolution, came just a day after three Tory MPs resigned from the party over Theresa May’s handling of Brexit and the risk of no-deal.

Anna Soubry, Sarah Wollaston and Heidi Allen joined The Independent Group started earlier this week by seven breakaway Labour MPs sick of Jeremy Corbyn’s leadership.

The three former Tories said their old party had been hijacked by the European Research Group [ERG] of hard-right Brexiter MPs led by Jacob Rees-Mogg.

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Mr Mundell called the ERG “Brexit purists”, adding: “I don’t think anybody out there would in any way equate the ERG with the Scottish Conservatives.”

Asked if he would resign from his party or the cabinet if Mrs May resolved to have a no-deal Brexit, he said: “I’m most certainly not leaving the Conservative party.

“I do not want to be part of the soap opera, psychodrama of people threatening to resign.

“I’ve been clear about the threat to the Scottish economy, and I believe to the continuance of the United Kingdom, of a no-deal Brexit.

“One of the reasons Nicola Sturgeon and the SNP are so keen to get us to a no-deal Brexit is that they realise as well that it is a threat to the continuance of the United Kingdom, and that’s why they’ve been trying to bring it about by at every opportunity supporting a no-deal Brexit in the votes [in Westminster, by opposing Mrs May’s deal].”

Pressed a second time on a resignation from cabinet, he said: “What I’m determined to do is to prevent a no deal Brexit happening, for the damage that that would do in Scotland, and the damage I think it could to the Union. So I will do everything I can, and whatever I deem necessary, to prevent a no deal Brexit coming about.”

It was reported this week that Mr Mundell was one of four ministers who told Mrs May that they would rebel if she did not delay Brexit beyond March 29.

The group said that if there was still no agreement on her deal they would back a cross-party amendment for parliament to seize control of the process.

If they did not resign, Mrs May would be forced to sack them.

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The others in the group are Works and Pensions Secretary Amber Rudd, Business Secretary Greg Clark, and Justice Secretary David Gauke.

Asked about the report, Mr Mundell did not deny it, but said: “I don’t comment on private conversations I’ve had with the Prime Minister. What I have said to her, repeatedly, is that a no deal Brexit is a very bad outcome for Scotland and the United Kingdom, and that we must do everything we can to avoid that outcome.”

He said: “I hope that the Prime Minister can bring forward something next week, or imminently, that can command the support of a majority of MPs."

Meanwhile, acting Scottish Tory leader Jackson Carlaw has downplayed the prospect of any splits in the party north of the border.

He said: “I don’t expect there to be any defections from anybody in Scotland. I think we are all very focused on the fact that in 2021 we have a key election to fight here in Scotland.

“We intend to be the next Government of Scotland, and that is the job that all Scottish Conservative MPs and MSPs are focused upon.

“But I understand that for many people this is a very, very difficult position.”

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He went on: “I think because we have a much more varied landscape with political parties in Scotland, there hasn’t been the same space for new political parties to grow successfully within it. I don’t know if that’s the reasoning. I certainly know that amongst my colleagues, they are all quite resolute. “They are members of the Scottish Conservative Party.

“They are focused on the objective we have in 2021. And while we appreciate that a lot of our colleagues down south find this whole position extremely difficult, I believe the right thing to do is to honour the result of the referendum. And that means supporting the deal that is going to come before the House of Commons again in a week or so’s time.”