The SNP’s Westminster leader has attacked Labour’s North Sea energy plans and vowed his party was committed to a “just and sustainable” future oil and gas sector.

Stephen Flynn said Labour’s proposal for a time-limited windfall tax on fossil fuel companies would result in “100,000 job losses”.

And he told the BBC’s Sunday with Laura Kuenssberg the Tory position was to “act like oil and gas will last forever”.

Sir Keir Starmer wants to raise the windfall tax on fossil fuel firms from 75% of excess profits to 78% while also extending it to 2029.

The Conservatives last week said the proposals were “based on fantasies” but Labour said the government had not made enough progress on the transition to renewable energy.

Mr Flynn also denied the SNP had given up on independence and said it would feature in the opening line of its manifesto when it is launched.

Scottish political leaders last week went head-to-head over the future of the North Sea oil and gas industry in the first TV debate of the general election.

When it was put to Mr Flynn, speaking from Peterhead, that the SNP had softened its stance on new oil and gas licences, he said: “What we believe in is a just and sustainable transition that protects the future employment of the tens of thousands of people who live behind me.”

He added the party would create “the new net zero jobs of tomorrow” and accused Labour of plans to “scrap 100,000 jobs”.

Last week BBC Verify examined Mr Flynn’s claim, which equates to roughly the number of jobs that Scotland’s oil and gas industry supports in the wider economy.

Those figures come from an independent estimate carried out for Offshore Energies UK (OEUK), a trade association.

But BBC Verify concluded it was misleading to suggest Labour’s plans put all of those jobs at risk.

Labour has said it would not issue new oil and gas licences, and would extend the windfall tax on energy companies, which OEUK says could threaten some jobs.

But the party has pledged not to overturn existing licences and says that oil and gas would still be part of the energy mix for decades to come

Mr Flynn also condemned Labour’s decision to ditch its policy of spending £28bn a year on its green investment plan.

And he accused the Conservatives of “almost becoming climate deniers”.

Mr Flynn was challenged over his criticism of Labour’s plans for a 78% windfall tax on North Sea energy companies.

A windfall tax is used to target firms which benefit from something for which they were not responsible.

Labour has proposed increasing it, while the SNP wants it maintained at the current level, which is about 75%.

Mr Flynn said the increased revenue from Labour’s plans would not reduce energy bills but rather “flow into nuclear power projects in England”.

He added the job figures were calculated by independent investment experts and had the Unite union saying it would result in workers being put “on the scrapheap”.

Mr Flynn said: “We need to make sure that we have a just transition that allows us to meet our climate targets.”

Labour’s Ian Murray later said the SNP had “zero credibility” on the economy and was “all over the place” when it came to energy jobs and security.

He said: “Stephen Flynn thinks a nurse on £29,000 a year should pay more tax but the oil and gas giants taking in billions of pounds in profits shouldn’t.

“That’s nonsense from a party that can’t give a straight answer on oil and gas.”

Mr Murray said Labour would establish GB energy, which would be based in Scotland, and transform the country into a “clean energy superpower”.

Scottish Greens co-leader Patrick Harvie told BBC Scotland’s The Sunday Show he wanted to see a move away from fossil fuels “as fast as possible”.

He also argued fossil fuels were a “thing of the past” and called for a focus on renewables.

Last week Scottish Conservative leader Douglas Ross said neither the SNP nor Labour would protect the North Sea industry.

During an STV leaders’ debate he said the SNP were against new oil and gas licences and accused Labour of having “dangerous plans” for the industry.

Mr Ross also referenced a report from the Aberdeen and Grampian Chamber of Commerce.

It criticised SNP and Conservative energy policies but said Labour could make the situation “even worse” by extending the Tories’ windfall tax on oil and gas profits and removing some tax breaks for investment.