IAN Blackford has insisted his threat that SNP MPs will cause “maximum disruption” to Theresa May’s agenda at Westminster over Brexit is not an idle one but declined to say precisely what it would involve.

The Nationalist leader at Westminster told the SNP conference earlier this week: “If contempt continues to be shown to the people of Scotland and our parliament, SNP MPs will not hesitate in causing maximum disruption to this Tory Government’s agenda when and where Scotland needs us to.”

Asked what “maximum disruption” would entail, Mr Blackford replied: “I’m not talking about gimmicks, I’m talking about us doing our job but we will do it on the basis of what parliamentary procedure allows us to do…We have a responsibility to show leadership and we will use parliamentary procedure to achieve that. I can’t go into detail as to what we will do.”

He went on: “Is this a bluff? Do we have an idea of what we can do? I tell you absolutely yes we do. It’s not a bluff. Timing is everything. I’m not saying it will be in the next couple of weeks but we will do things when it is right to do so.”

In June, PMQs descended into chaos when Mr Blackford led his MPs out of the Commons chamber, a tactic John Bercow, the Speaker, branded a “stunt”.

Asked if the SNP could disrupt the upcoming Budget, the Highland MP replied: “I’m not going to get drawn into when it is. Things will happen at the right time. Let’s wait and see…The most important thing is going to be EU withdrawal and I will leave it at that.”

At the time of the walk-out some SNP MPs suggested the "template" for their frustration strategy should be the obstructionist actions of Charles Stewart Parnell and the Irish Nationalists of the 19th century. These included making overly lengthy speeches, tabling numerous amendments and calling continual votes.

But Mr Blackford played down the comparison with Parnell, saying they were “different times”.

He added: “We will make sure we are effective and our voice is heard.”