The entire cohort of SNP MPs walked out of the Commons on Wednesday after their Westminster leader, Ian Blackford, was expelled for challenging speaker John Bercow during PMQs.
Blackford was repeatedly told to take his seat after he demanded a vote on the House sitting in private, after Theresa May refused to bring forward emergency legislation on her Brexit plans.
The SNP claim the EU Withdrawal Bill opens the door for a Westminster power grab which takes away from the Scottish Parliament and undermines devolution.
Many are also furious Scottish MPs were given minutes to discuss key Lords amendments on Tuesday night.
Rising to ask a question during the session, Blackford said: “The Prime Minister gave a commitment that she would treat Scotland as a union of equals.
“Yet, last night, she pressed ahead with a power grab in direct opposition to Scotland’s elected parliament.
“The Prime Minister silenced Scotland’s voice, having broken constitutional convention, and plunged Scotland into a constitutional crisis, will the PM now commit to bringing forward emergency legislation so the will of Scottish Parliament can be heard and, more importantly, respected?”
May replied that the Bill ensured a “significant increase in decision-making powers” for Holyrood and that says 80 new powers will “flow direct to Holyrood”.
But MSPs at the Scottish Parliament refused to give their blessing for May’s Bill – something Blackford says has been ignored.
“I really do hope that the people of Scotland listened very carefully to what the PM said,” he said.
“The reality of the situation is that powers enshrined under the Scotland Act in 1998 are being grabbed back by this House.
“It is a power grab and MPs from Scotland were not even given the courtesy of debating it last night.
“It is a democratic outrage.”
Turning to the speaker, he said: “Under the circumstances, given the disrespect shown, I have got no option but to ask that this House sits in private.”
He then demanded a vote on the issue, something which Bercow refused to consent to until PMQs had concluded.
“I’m not hearing that at this time and it is my clear understanding that I’m not obliged to do so,” said the speaker.
Blackford then refused to sit back down and Bercow asked him to leave due to the “repeated and insistent refusal to resume his seat when so instructed” the Commons and not return for the rest of the day.
The party’s Westminster leader was then followed by all other SNP MPs.
Speaking afterward, Blackford said: “I called for the House to sit in private – using parliament’s own procedures to ensure Scotland’s voice is heard on Brexit. Proceedings on the EU Withdrawal Bill last night were a democratic outrage and the Scottish Parliament must be respected.
“The Prime Minister gave a commitment that she would treat Scotland as part of a ‘union of equals’. Yet last night she pressed ahead with a power-grab in direct opposition to Scotland’s elected Parliament.
“We hear from the Prime Minister about respecting devolution. But the Prime Minister has ignored Scotland.”
He added the issue would “haunt the Scottish Tories for a generation”.
Asked by reporters if it was a stunt, he replied: “Under standing orders I was entitled to push for that vote today on the basis of the lack of respect that the Conservative government and Theresa May have shown. It is not acceptable.”
SNP leader Nicola Sturgeon has said she was “right behind” Blackford and accused Westminster of treating Scotland with “contempt”.
Scottish Secretary David Mundell said the SNP was about to be granted a debate on the devolution aspects of the EU Withdrawal Bill by the Government.
He added: “Disappointed, if not surprised, that if they really felt so strongly about it, they chose a stunt over holding the Government to account.”
Scottish Conservative MP Kirstene Hair, meanwhile, said: “This rehearsed move just demonstrated that the SNP care more about headlines than actually achieving anything for Scotland. They are the masters of manufactured grievance and the people of Scotland are sick of it.
“The SNP have played games with the constitution, played games with Brexit and now are playing games with Parliament. It is a joke.”
And the SNP faced claims it had pre-planned the walkout after a piece of paper entitled ‘points of order’ was found on the SNP benches.
It had several bullet points with a ‘insert outrage/disappointment’ next to it.
Although thought to be notes related to the previous day’s debate on the EU Withdrawal Bill amendments, Scottish Tory Andrew Bowie claimed the paper was evidence the party planned to kick up a stink about process.
Labour’s shadow Scotland secretary Lesley Laird, meanwhile, said: “Today’s stunt by Ian Blackford and his colleagues simply emphasises further that they have one aim - to play political games rather than standing up for Scotland.
“They had a chance today to question the Prime Minister and secure a three hour debate on devolution. Instead, they chose to flounce out of the House of Commons.”
Former Lib Dem Tim Farron called said Blackford and his colleagues appeared “shallow” and had “silenced yourself”.