DOUGLAS Ross was reportedly feared to be on the brink of quitting his position as Scottish Conservatives leader in a rage over the upcoming Budget.

The Moray MP was embroiled in a “stand-up row” with Rishi Sunak at a drinks reception hosted in the Prime Minister’s parliamentary office, reports The Telegraph.

The Scottish Tory leader is said to be furious with Conservative high command over plans to cut National Insurance – funded by an extension to the windfall tax on oil and gas giants.

Ross is fundamentally opposed to the tax on energy profits, believing it will harm the economy in Tory-voting parts of Scotland.

But the Chancellor is thought to have pressed ahead with the measures and is reportedly planning to fund a 2% cut to National Insurance with taxes on vapes, tobacco and an extension of the windfall tax.

READ MORE: Douglas Ross red-faced as Chancellor set to ignore windfall tax pleas

The Telegraph reported that Ross’s “heated” complaints to the Prime Minister fell on deaf ears after warning Sunak the windfall tax would hammer the Tory vote north of the Border.

He was said to have then taken up his case with Chancellor Jeremy Hunt, who is also said to have batted away the Scottish Conservative chief’s complaints.

Ross reportedly then had to be talked down from quitting his position by Chief Whip Simon Hart, with Scottish Secretary Alister Jack (below) also called in to soothe his ire.

The National: Alister Jack

He is said to have agreed to keep a lid on his anger until after the Budget is announced on Wednesday afternoon but is expected to make public his concerns later.

The exchanges were said to have happened at an event hosted in the Prime Minister’s parliamentary office on Monday night.

All 348 Tory MPs were invited to the soiree and around 80 to 90 turned up, according to The Telegraph.

Sunak and Hunt are forced to walk a tightrope with Wednesday’s Budget, with some Tories pushing for lower taxes despite an official forecast warning the Chancellor he had significantly less room for manoeuvre on tax cuts than previously expected.

The Office for Budget Responsibility warned the “fiscal headroom” – the amount of money available to Hunt to use without breaking his own borrowing rules – had shrunk from more than £30 billion last autumn to less than £13bn.