SNP leaders have signalled that the gloves are off in their bid to win the best deal for Scotland on the devolution settlement.
Dramatic scenes saw SNP Westminster leader Ian Blackford expelled from the House of Commons, followed by all his MPs, after Prime Minister Theresa May refused to alter her EU Withdrawal Bill.
Mr Blackford had used a little-known parliamentary procedure to call for an immediate vote in the middle of PMQs, leading to a stand-up row with the Speaker.
The P&J can reveal the brains behind the move as Aberdeen North MP and SNP Westminster deputy leader Kirsty Blackman, who dug out the procedure in the parliamentary bible Erskine May.
Mrs Blackman said her party had played by the rules without success and was now running out of options to be heard.
“We have to do everything we can to stand up for the people of Scotland,” she said. “We have tried at every opportunity to say ‘we don’t agree with what you’re doing’ to the UK Government.
“The actions of the Tories have fundamentally altered the relationship between the SNP, the Scottish Government and the UK Government.
“We have already taken every possible action within the rules and today we have taken a different tactic, although still within the rules, in order to make sure it is clear quite how unhappy we are.
“We’re going to do whatever we can, whatever we can think of.”
Ross, Skye and Lochaber MP Mr Blackford said the “outrageous treatment” of Scottish MPs being unable to debate the devolution aspects of the Bill justified his actions yesterday.
“This is a serious situation and a constitutional crisis,” he said. “The power grab has now in effect happened.
“Where we can have an impact on government business we will do that.
“What we do will be determined by the rules of the House.”
Scottish Secretary David Mundell said the walkout was not justified as the EU Withdrawal Bill reflected the Sewel Convention governing the devolution settlement.
“The Sewel Convention has been applied,” he said. “It talks about normal events and Brexit cannot be described as normal.
“My job is not to roll over to Nicola Sturgeon and do exactly what she says, even if that is Mr Blackford’s role.”