BORIS Johnson’s senior aide on the Union, Oliver Lewis, insisted the Prime Minister keep using the “Scottish nationalist party” to annoy the SNP, it has been claimed.

Lewis, who quit his Downing Street role on Friday after two weeks, urged Johnson to refer to the Scottish National Party as “the Scottish nationalist party” at Prime Minister’s Questions, a move that angered Ian Blackford, the SNP leader in Westminster.

“Oliver’s view is that there is a lot we can do to discombobulate the SNP,” a friend of Lewis’s told the Sunday Times yesterday. “The nationalist thing has diverted them into bickering about how nationalist they are.”

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Johnson has been repeatedly rebuked for using the incorrect name of the SNP at the weekly questions in the Commons. He did so on January 13, on December 30 and on further previous occasions.

On January 13, Blackford had raised grave concerns of fishermen in his constituency, who warned their businesses were being wrecked by Brexit red tape.

The Prime Minister responded by claiming the UK Government was providing £100 million of support to the UK fishing industry.

He added: “It is the policy of the Scottish nationalist party, not just to break up the United Kingdom under their harebrained scheme, but also to take Scotland back into the EU and hand back control of Scottish fisheries to Brussels.”

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Blackford responded: “I’m amazed that the Prime Minister continues to traduce the name of the Scottish National Party.

“He’s been told before and he really should get it right.”

On December 30, Speaker Sir Lindsay Hoyle stepped in to caution Johnson at Prime Minister's Questions for calling the SNP "the Scottish nationalist party."

Blackford interrupted him to ask the Speaker "Can you point out to the Prime Minister that the name of my party is the Scottish National Party?"

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Hoyle replied: "In fairness I have pointed it out in the past. It is the Scottish National Party, Prime Minister."

Johnson claimed he did not get the name wrong, adding: "I wish the right honourable gentleman to know that I am using the word nationalist with a small N and I don't think that he would disagree with that which is semantically justifiable under the circumstances."

Lewis, the former head of research at the Vote Leave campaign under Dominic Cummings, acted as the de facto deputy to David Frost when he negotiated the UK’s Brexit deal.

No 10 has been beset by bitter internal power struggles, most dramatically the departure in November of Cummings, Johnson’s chief aide, shortly after the resignation of another Vote Leave alumnus, the then head of communications, Lee Cain." 

Stewart Hosie MP, the SNP's Shadow Cabinet Office spokesman, said: "Oliver Lewis was out of the door of the failing Union Unit before he even had a chance to set his desk - following the steps of Luke Graham. 

"With two heads of the unit quitting their roles in the space of a fortnight, the reality is that the Tories' anti-independence campaign is crumbling and its union unit unravelling. 

"However, the entire episode raises very serious questions for Boris Johnson over how much of the taxpayers' money he has wasted on this shambles.

"Taxpayers have the right to know how much money is being splurged on Tory advisors - including Oliver Lewis, whose only campaign idea so far appears to revolve around mispronouncing the party's name."