Smaller independent North Sea operators say it's them that are paying the price for the Energy Profits Levy (EPL).
Investment in the basin has fallen sharply since the introduction of the windfall tax on oil and gas profits. Last year, UK oil and gas production was at its lowest since 1977 at a little more than 1.2 million barrels a day.
Further losses of investment could mean even more jobs go, as industry has repeatedly warned.
Shares in Harbour Energy, the UK's biggest independent producer, have fallen 23% since Russia's invasion of Ukraine, while shares in Serica Energy are down 37%.
"The continuous decline in production and jobs isn’t good from a macro perspective," said EnQuest's Amjad Bseisu.
He added: "There are many [producers] that have exited, or are exiting the UK."
'Little appetite' to invest in UK
The additional 35% tax rate came to force in May 2022 in the wake of Russia's invasion of Ukraine.
Since Q3 2022, gross operating surplus of North Sea operators has dropped from £11.1bn to just £2.3bn in the final quarter of 2023. The price of Brent crude oil has risen just 8% since the end of 2021, months prior from the outbreak of war in Eastern Europe.
Meanwhile, consultancy firm Wood Mackenzie says buyers are showing "little appetite" to expand in the UK North Sea or enter the UK continental shelf.
The firm estimates that £16bn in potential investment could be lost due to political uncertainty.
Mark Lappin, chair of Deltic Energy, said: "When I started out in this industry there were only major companies mostly with global presence operating in the North Sea but in recent years they have all been moving out."
Political uncertainty
North Sea confidence slumped further this year when Labour rolled back on its Green Prosperity Plan and pledged to lift the additional tax rate to 38%, as well as removing investment allowances.
It results in warnings of hundreds of thousands of jobs from various industry bodies.
And at the Spring Budget, Jeremy Hunt extended the tax to 2029, despite the protestations of his Scottish parliamentary colleagues.
Ryan Crighton, Policy Director at Aberdeen & Grampian Chamber of Commerce, commented: “After four tax changes in two years, the appetite for investment in the UK continental shelf is in a worrying place."