IAN Blackford accused Theresa May of being a “liar” during a heated exchange in the Commons.

The Prime Minister had come to Parliament to ask MPs to “hold their nerve” over Brexit, begging them to give her more time for negotiations.

But the SNP’s Westminster leader was palpably angry with the Tory, questioning her honesty four times in his short statement.

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It started partly because she claimed that she had wanted Brexit sorted before December.

May was, he said, living in a “parallel universe”.

The National:

“We’ve just heard from the Prime Minister that she wanted this concluded in December. Talk about rewriting history,” he said.

“It was the Prime Minister that denied us the right to have the meaningful vote. And to try and rewrite history, and she sits there laughing.

“You know, sometimes you should be honest with yourself, never mind being honest with the people of the United Kingdom.”

Blackford then asked the Prime Minister if the UK Government had an economic assessment of the impact of her deal on the economy: “You’re asking this House to vote on your deal and you can’t even be honest on the economic impact.”

Responding, May said she had “published an economic analysis of the Government’s proposals.”

A furious Blackford shouted “that’s not true”.

May then hit back, saying the MP for Ross, Skye and Lochaber, had “inadvertently misled the House” prompting Blackford to call her a “liar”.

The National:

Parliament’s strict rules forbid MPs from questioning the honesty of their colleagues. A politician suggesting another is untruthful can find themselves kicked out of the chamber.

“If that word was used without equivocation or qualification that word must be withdrawn, at once. At once,” Speaker John Bercow said.

He added: “If a member on the front bench used, that word – I’m sorry, I’m not debating, I’m not arguing, I’m not negotiating, that word must be withdrawn. At once.

“That word was used by the leader of the SNP, if so and I want the debate to continue and it will, if so, I simply ask the right honourable gentleman to withdraw that word. He cannot accuse another member of this house of dishonesty.”

Blackford then offered a qualified withdrawal of his accusation, saying it was only out of “courtesy” to the Speaker.

That infuriated Tory MPs who felt it was insincere, but Bercow allowed it.

Tory MP John Lamont tweeted that Blackford was a “disgrace” and “letting down Scotland.”

His colleague Douglas Ross accused the SNP leader of being “shameful”.

May carried on to say that an economic analysis of her deal was “published before the Withdrawal Agreement was put before the House.”

But that report, released in June last year, looked at May’s Chequers plan, which set out what she had hoped to achieve in negotiations.

It did not look at what was in the finalised Withdrawal Agreement or Political Declaration.

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Late last year, the cross-party Treasury select committee said the report could not be used “to inform Parliament’s meaningful vote on the Withdrawal Agreement” as the “information provided includes no analysis of the backstop.

They added there was also no short-term analysis of any of the scenarios, including on public finances and on regional and sectoral job losses and gains. “

Afterwards, Blackford said May had clearly “lied to Parliament and by extension to the people of the UK.”