DAVID Mundell was accused of playing with his iPhone while “stabbing the Scottish Parliament in the back” over the transfer of devolved powers post Brexit in a stormy emergency devolution debate.

SNP Westminster leader Ian Blackford urged the Scottish Secretary to stand up and speak in the Commons having already insisted he was “unfit” for the job and has “no credibility”.

Blackford added: “There is no coming back from this. He must resign or the Prime Minister must sack him.”

He warned the UK Government’s approach to Scotland over the European Union (Withdrawal) Bill, which transfers EU law into UK law, was a return to the “days of the poll tax” under Margaret Thatcher.

Just 15 minutes were left for debate on devolution changes linked to the Bill when MPs considered amendments made by the House of Lords last Tuesday. No Scottish MP was allowed to speak in the debate which was addressed only by Cabinet Office minister David Lidington.

The Scottish Parliament voted to refuse to grant a legislative consent motion for the key Brexit legislation and by proceeding with the bill without it the SNP says Westminster overturned an important constitutional convention.

Blackford told the Commons: “I regret the fact the Secretary of State for Scotland is not down to speak tonight. I’m going to give him another opportunity – stand up and defend the indefensible.

“He can’t. He’s sitting there playing with his iPhone – playing with his iPhone and stabbing the Scottish Parliament in the back.

“Come on, come on! Up you get, come on! Speak up, come on, speak up.”

Speaker John Bercow intervened to calm tempers and advised Blackford it was a matter for Mundell on whether or not he wanted to intervene.

Mundell was cheered as he stood up and moved to the despatch box, telling the Sewel convention debate: “This speech [by Blackford] is not worthy of a response from me.”

He added: “He calls for respect, but focuses entirely on the personal in his comments.

“This may be a performance for his colleagues, it may be a performance for his core voters, it doesn’t impress Scotland.”

Blackford later said there were only “days left to save Scotland’s devolved settlement” and encouraged Theresa May to bring forward emergency legislation to remove parts of the Bill to ensure it matches what the Scottish Parliament voted for.

He said: “That is the only way the UK Government can undo the damage it has caused, and the only way the Tories can show the people of Scotland that their Scottish Parliament’s rights are recognised and respected.

“That is the only way we can save devolution in Scotland.”

During the debate Blackford reminded the Conservatives that by failing to back devolution in 1997 it had lost considerable support in Scotland, and warned the party that such a situation would happen again.

Scottish Tory MP Douglas Ross stated the SNP had not supported devolution – a claim rejected by Blackford who said his party had backed it both in the 1979 and 1997 referendums.

Several SNP MPs shouted “red card” at Ross, who is also a part-time football referee, as Blackford hit back saying one of the reason why 74% of Scots supported devolution in 1997 was because the country “had suffered so badly from the years” of Margaret Thatcher and John Major’s Conservative governments, which he said “had “destroyed communities up and down the land”.

He said: “And what we see today is the Scottish Conservatives behaving exactly as they did in the past.

“I will make this prediction, you will pay a price again because what you’ve had done, is you have stabbed the Scottish Parliament and the people of Scotland in the back by taking these powers back.

“Scotland is watching and it is not just the supporters of the SNP who are alarmed, those that cherish our parliament are outraged.”

Scottish Tory MPs later weighed in to offer support to the government and rounded on the SNP.

Colin Clark said: “The SNP are acting as a fifth column, industry can now see Holyrood cannot be trusted to represent them, jobs will be undermined.”

Brexiteer MP Ross Thomson criticised the SNP and claimed some of his staff had been targeted as a result of the SNP’s debating style.

He called for Scottish Brexit minister Mike Russell to step down, blaming him for the lack of agreement between the two governments.