Scottish Secretary David Mundell has said he will not join breakaway pro-EU colleagues in leaving the Conservatives.

Asked if he would leave the the party or the Cabinet in the event that a no-deal Brexit becomes the Government’s position, he said: “I’m most certainly not leaving the Conservative Party.”

“I’m disappointed that colleagues have chosen to leave.”

He said he hoped the three Conservatives who walked out on Wednesday to join eight ex-Labour MPs in the Independent Group (TIG) would have an opportunity to return at some point.

Mr Mundell made the comments following a speech in Edinburgh to mark the 20th anniversary of the establishment of the Scottish Parliament.

Questioned on reports that he is one of four Cabinet members to tell Theresa May she must agree to delay Brexit by extending Article 50 to avoid a no-deal exit, or lose their support, he said: “I don’t comment on private conversations that I’m having with the Prime Minister.

“But what I have said to her repeatedly is that a no-deal Brexit is a very bad deal for Scotland and the United Kingdom and that we must do everything that we can to avoid that outcome.”

Pressed further if he would resign his ministerial role in the event of a no-deal, he said he would “do everything I can, and whatever I deem necessary, to prevent a no-deal Brexit coming about” but would not be setting “strict parameters on what that may or may not be”.

Mr Mundell said he still believes a deal and an orderly Brexit is achievable.

He added: “It’s just no good anymore for people to stand up and to say they don’t want a no-deal Brexit, they don’t want the chaos and disruption that that would bring, and then vote for it.

“I find astounding the position of the SNP and the Scottish Government. They produce a report telling us what we all know – that a no-deal Brexit would be a very bad thing for Scotland and indeed the UK.

“But every time there is the chance to vote on that issue the SNP trot through the no-deal lobby, when their 35 MPs could end up being the difference between whether we leave without a deal or whether we don’t.”

The Scottish Secretary said the SNP realise a no-deal Brexit is a “threat” to the unity of the UK and “that’s why they are contriving to bring it about, by, on every opportunity, supporting a no-deal Brexit in votes”.

During his speech, he said leaving the EU is an opportunity to strengthen devolution within the UK and rejected Scottish Government claims that Brexit will “damage devolution”.

He said: “I do not believe Brexit will damage devolution. I want it to strengthen devolution, and I believe that can and will happen.”

Mr Mundell branded SNP assertions that key Brexit legislation is a “power grab”, which could see Scotland lose out on powers returning from Brussels, as “invented grievance” and “complete fantasy”.

He added: “What these myths amount to is an attempt to undermine devolution – to sweep away the 98 settlement – by people who do not support devolution because they want independence.”

SNP depute leader Keith Brown (Jane Barlow/PA)

However SNP depute leader Keith Brown said: “The Tories fought tooth and nail against devolution in the first place – and their attitude has barely changed since.

“David Mundell is perfectly content with imposing a hard Brexit on Scotland against our will – while making a powergrab on areas the Leave campaign pledged would come directly to Holyrood.

“After Theresa May trampled all over David Mundell’s self-declared red-lines, if he had any credibility he would have resigned months ago.”