DOWNING Street has brushed aside the threat from the SNP leadership to “frustrate” UK Government business on a day by day and week to week basis.

Following Ian Blackford’s eviction from the Commons chamber during Prime Minister’s Questions followed by a mass walkout of his Nationalist colleagues, the party leader pledged to be “robust in using parliamentary devices to make sure we can hold this Government to account…and frustrate what it is seeking to do”.

He also warned his party would use Commons procedures to oppose Theresa May’s Government in every conceivable way, which would have an impact on its business on a “day to day and week to week basis”.

On the back of the Conservative administration pushing ahead with the flagship EU Withdrawal Bill and in light of only 15 minutes being devoted to Commons exchanges on Tuesday evening, Mr Blackford accused the Tories of a “democratic outrage” and of returning to their “anti-Scottish” days.

When asked about the SNP leadership’s threat to frustrate UK Government business, the PM’s spokesman said: “Look, we have sought to work constructively with the devolved administration and the SNP leadership throughout this process and that will continue to be our aim.

“We, obviously, debated at length the subject of the devolution settlement. We reached an agreement with the Welsh Government, we haven’t yet reached one with the Scottish Government but we look forward to continue to work closely with them.”

Asked again about the threat of frustrating Government business, he replied: “It’s a matter for the SNP what they choose to do in Parliament.”

His remarks came ahead of a Commons statement on the Brexit and devolution issue from David Mundell, the Scottish Secretary, which was expected to generate yet more heat on the subject.

After Wednesday’s Westminster drama, the SNP leader vowed to take "whatever action is necessary" to press its case at Westminster in the wake of the "constitutional crisis" sparked by the row over Brexit powers.

The Highland MP again warned the UK Government that "this is not the end of the matter, this is the beginning", as he told how the SNP at both Westminster and Holyrood would now work to "frustrate" Mrs May's administration.

He told BBC Radio Scotland's Good Morning Scotland programme that the Tories were "obstructing devolution" and said the SNP "simply are not going to stand back and allow that to happen".

"Together with my colleagues in government in Edinburgh there will be a very robust defence of our parliamentary democracy, our parliamentary sovereignty and the rights of the Scottish people.

"I will make sure we can frustrate as much as we possibly can what the Government are doing.

"We will remain civil, we will remain polite, we will remain courteous but they need to understand that a line has now been crossed and the Conservatives are enacting legislation without the support of the Scottish Parliament, with lack of consent. We are now in different territory," declared Mr Blackford.

He said British politics was now at a “very, very serious moment” because Westminster, without debate, stripped powers that should be returning to the Scottish Parliament under the 1998 Scotland Act.

"It is a constitutional crisis," insisted the SNP leader. "It is regrettable that the UK Government have pushed ahead with this, that there has been no respect shown to not just the Parliament of Scotland but the people of Scotland."

Mr Blackford vowed: "Together with my colleagues I will be continuing to press the issue to make sure that Scotland's voices are heard. This is not the end of the matter this is the beginning."

But Scottish Tory MP Andrew Bowie hit back at claims that the Withdrawal Bill was a Westminster "power-grab".

"Due to the legislation we passed this week 120 extra powers will be going to Holyrood, this is going to enhance the devolution settlement, not in any way restrict it," he stressed.

The West Aberdeenshire and Kincardine MP told the same programme there "should have been a much more substantial debate" on the issues but blamed Labour for this, saying most of the time had been taken up with votes in the Commons that had been pressed for by Jeremy Corbyn's party.

He also hit out at Mr Blackford, saying: "By walking out of the chamber in a pre-prepared parliamentary stunt he actually gave up the opportunity to hold the Government to account and actually have a debate about the very issue he is complaining he hasn't had a debate on."