Labour’s plans for a 78% windfall tax on the profits of energy firms would "cast tens of thousands of hard-working men and women on the scrapheap," the Aberdeen and Grampian Chamber of Commerce has warned. 

It comes after investment bank Stifel said the best-case scenario of the policy would be 20,000 jobs lost. Their worst-case scenario was 100,000 jobs lost.

They said the proposal could lead to a cumulative loss of £40bn of investment within a decade and cost the Treasury £20bn in lost tax revenues.

The bank also warned that it could mean the UK importing 80% of its gas supply by as early as 2030.

READ MORE: Keir Starmer drops Labour £28bn green spending pledge

Details of the “proper windfall tax” were unveiled last Thursday as Sir Keir Starmer ditched his commitment to spending £28bn a year on green investments.

The new plan would see Labour hike the government’s existing windfall tax from 75 to 78% and extend the levy by a year to 2029.

Crucially, it would also close what Rachel Reeves has described as “loopholes” in the existing windfall tax, potentially scrapping the current investment allowance which sees oil and gas producers get 91p in tax relief for every £1 they invest.

The party said the proposals would raise £10.8 billion over five years, helping to pay for a £23.7 billion uplift in green spending over five years.

Writing in the Press and Journal, Ryan Crighton, the policy director of the Aberdeen and Grampian Chamber of Commerce accused Labour of being “backstabbers".

He said: “Heading to Scotland to betray people in the pursuit of money and power has become very fashionable in 2024 thanks to the TV show The Traitors.

“However, the back-stabbing stars of the hit series have nothing on Labour, who are heading for Glasgow for their Scottish Conference [on Friday] having just delivered one of the biggest betrayals in Britain's industrial history.”

He said the party’s policy would “potentially wipe out five times as many” jobs as the closures that sparked the miners’ strikes.

Mr Crighton added: “Labour - the party of workers and unions - is happy to cast tens of thousands of hard-working men and women on the scrapheap and place a world-class Scottish industry on death row.

“It does not matter what your political persuasion is, a policy that costs 100,000 jobs is a bad one.”

He said that when the industry in the North East welcomed Sir Keir Starmer and Ed Miliband to Aberdeen in November, "they looked us in the eye and told us they wanted to work with the energy industry to deliver a transition that leaves nobody behind."

Mr Crighton added: "They say they want to work in partnership with industry but just like last summer, when they sprang plans for an exploration ban, this windfall tax extension has been done with zero engagement.

"Right now, Labour's energy policy is an absolute disaster, and the party needs to sit down with industry and rewrite it from scratch if we are to retain any hope of remaining a global energy hub."

READ MORE: Jackie Baillie: 'I'm impatient for change. The SNP has been too timid'

The promised hike was also attacked by the SNP’s Stephen Flynn, who said it “would be a level of de-industrialisation that Margaret Thatcher could only dream of.”

However, the SNP has previously called for a “broad-based” windfall tax on all major companies that made “excessive” profits.

Mr Crighton criticised the party, saying it had been "politically neutered by the Greens."

He said: “The SNP of old would be standing up for the tens of thousands of Scots now facing an uncertain future. The prospect of a Westminster government shutting down Scotland's biggest industry would be election manna from heaven.

"However, hamstrung by their ill-conceived presumption against oil and gas, and politically neutered by the Greens, Humza Yousaf has no moral high ground to occupy on this issue.”

Stifel managing director for oil and gas Chris Wheaton said 2024 could “be the last year of major spending in the UK North Sea” because of concerns over Labour’s tax policies.

He said: “The best case would be driven by no step-change in tax, managed decline of the existing energy mix i.e., the UK’s oil and gas, and also continued incentives to invest in wind, electrification and maybe hydrogen and CCS.

“The worst case would be aggressively going after the offshore industry for additional tax revenues because you think it’s an infinite source of revenue with no downsides at all, and that’s not the case because there are going to be downsides into investment, jobs and energy security.

“The worst case actually would be no new drilling at all. Not just exploration, but any kind of new developments – you can drill out existing licences but then that’s it – that kind of regulatory intervention would be the worst possible case scenario.”

Responding to the comments, Labour's Shadow Scottish Secretary Ian Murray said "People in the North East and across the UK are feeling the pinch from soaring energy bills. 

"Labour's plans will ensure oil and gas giants making eye-watering profits from the cost of living crisis pay their fair share towards the delivery of cleaner and cheaper energy.  

"Jobs are at the heart of Labour's Green Prosperity Plan - we will not only protect existing jobs in the North East but will bring the jobs of the future to the region.  

"We will set up a publicly-owned GB Energy Company here in Scotland, which will support the creation of thousands of clean energy jobs and help deliver clean energy by 2030.

"Labour's plans will cut bills, create jobs, deliver energy security and unleash Scotland's potential as a clean energy superpower."