THE head of Boris Johnson’s Union unit wanted to establish a pro-UK grassroots movement but quit after the Prime Minister refused to give him new powers to pursue a “hardball” strategy to confront the SNP, according to a report today.

Oliver Lewis, who resigned from Downing Street on Friday, had mapped out a strategy to refuse a referendum and challenge First Minister Nicola Sturgeon on the Scottish Goverment's record ahead of the May election.

In a plan modelled on Vote Leave’s success in the 2016 EU referendum, ardent Brexiteer Lewis wanted to set up a pro-Union grassroots organisation to counter the Yes movement.

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Lewis, who convinced Johnson to threaten to break international law in order to force through a Brexit deal, was prepared to “stretch the law to its limits” to prevent another independence referendum, the Sunday Times reported.

He had also urged Johnson to keep referring - inaccurately - to the SNP 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,” said a friend. “The nationalist thing has diverted them into bickering about how nationalist they are.”

A source familiar with Lewis’s blueprint said: “The plan was [to] ram home messages that have great resonance in Scotland that the public services have been decimated by SNP policies.”

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Lewis told Johnson he needed total control of the plan so it was clear that he was speaking with the Prime Minister’s authority. But he quit as head of the Union unit - set up to stop independence - when it became clear that would not be forthcoming.

No 10 sources said that Lewis wanted to be “far more confrontational” than Michael Gove, the minister who chairs the cabinet committee on the Union.

Insiders told the Sunday Times said that the departure of Lewis means the government adopt a less abrasive tone towards the SNP.

“The argument will still be that it would be dangerous at this time to have a referendum when there are far more important things to be dealing with,” said an informed source.

Lewis left his role in Downing Street on Friday after just two weeks.

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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 with the EU.

No 10 has been beset by bitter internal power struggles in recent months, 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.

Those departures were spurred after Cain’s promotion to chief of staff was blocked by Johnson’s fiancee, Carrie Symonds. The loss of Lewis is also likely to be seen as connected to the continued fighting for influence inside No 10.

Lewis replaced the former Scottish Conservative MP Luke Graham shortly after Johnson made a controversial lockdown visit to Scotland last month despite the First Minister raising questions whether the trip counted as essential, and therefore within the rules permitting travel.

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."

Lewis’s departure followed the unexpected promotion of Frost to a seat around the Cabinet table earlier this week, despite him not being elected as an MP.