ALEX Salmond is not pulling the SNP’s strings at Westminster, Ian Blackford has insisted, as he made clear he has no regrets over his bitter personal attack against David Mundell over Brexit.

Earlier this week, the Nationalist leader in the Commons intensified the political rhetoric when he denounced the Scottish Secretary as “yellow” for not speaking in a debate and a “dismal failure” in his role at the Scotland Office.

He accused Mr Mundell of “stabbing Scotland in the back” over the devolved powers controversy, declaring: “He fails to stand up for Scotland as a country, fails to stand up for our Parliament, he sees us as subservient. That's why the Secretary of State needs to go. He is quite simply unfit for the office he holds."

Mr Blackford’s remarks came just days after he was ordered from the Commons by the Speaker and led a mass walkout of SNP MPs from the chamber.

Following the dramatic event, Mr Salmond, who himself walked out of the Commons during Chancellor Nigel Lawson’s 1988 Budget statement, suggested he had been the SNP’s inspiration by telling the party leader that targeting interventions on key occasions was the way to make a successful protest.

"Certainly, that was my advice to Ian Blackford when he phoned me last Tuesday night and I was delighted to see him carry it through," explained the former First Minister.

But when the Highland MP was asked if Mr Salmond was pulling the party leadership’s strings at Westminster, he responded with a firm “No”.

Mr Blackford also insisted his angry remarks directed at Mundell were not meant to be personal.

“I was robust in how I spoke because the Secretary of State has failed to defend Scotland at every turn, he has been a complete failure,” he declared.

“I don’t wish to be personal about the Secretary of State but on the lack of ability in serving Scotland’s interest, as defined by the Government itself, it is not good enough.”

The party leader made clear he had not accused individual MPs of being “anti-Scottish” but, rather, Theresa May’s Government.

A Whitehall insider suggested the SNP leadership was losing the argument on the Brexit Bill, which was why it was resorting to “cheap personal attacks”.

Meanwhile, as Nicola Sturgeon, the First Minister, and Michael Russell, her Brexit Minister, headed for Guernsey to attend the British-Irish Council, David Lidington, the Cabinet Office Minister, who will also be at the meeting, stressed how, despite the strong disagreements with Edinburgh over the Brexit Bill, the UK Government was committed to improving the depth of its co-operation with the SNP administration.

“Whatever the inevitable political noise as we unpick the complexities of our membership of the EU, I will ensure that we maintain the depth of our ongoing engagement with the Scottish Government, including this week at the British-Irish Council in Guernsey. I hope that the Scottish Government will maintain their own side of that relationship.”

He added: “By working together, we will help secure a deal that sees us leave the European Union as a more modern country where all four nations have their voices heard but also as one United Kingdom; as the people of Scotland voted for in 2014.”