Hundreds of North Sea oil and gas discoveries could be abandoned as energy companies battle uncertain headwinds.
Currently there are "over 300" offshore finds that are not yet under serious examination for development, according to Professor Alex Kemp of Aberdeen University.
Most of the unexplored discoveries are "relatively small" - meaning it is unlikely firms will take the risk of investing in them for limited reward, says the leading petro-economist.
Uncertainties around oil and gas prices and the energy profits levy make it even more improbable that companies will explore potential reserves.
In terms of resources still in place in the North Sea, there is "still a large volume", said Prof Kemp, potentially between 10billion and 20billion barrels of oil equivalent (boe).
He told Energy Voice: "Our modelling has always shown that the majority of that would come from discoveries already made, rather than from brand new ones.
Not fully explored
"The problem is that a lot of these discoveries already made are not yet fully explored, and aren't under serious examination for development.
"There are reserves that fall into the probable and possible categories that are seriously being considered - but there's a lot more discoveries, over 300 for sure, not seriously being examined."
Prof Kemp added: "We have looked at the windfall profits tax and we think that it will adversely affect investment decisions - both for exploration and for development, particularly of relatively small fields."
Concerns about the windfall tax could also impact any fields uncovered as part of the 33rd North Sea exploration licensing round.
An investment allowance incentivises spending by oil and gas producers , but Prof Kemp said "not every company is in that situation", while some new entrants don't pay enough tax for it to make a difference.
Fears that companies would negatively respond to the fiscal changes have already materialised.
Cut to spending
TotalEnergies is cutting its North Sea spending, while Harbour Energy shunned the latest licensing round, as well as announcing job cuts.
Prof Kemp believes the impact of the windfall levy will continue to seep through, particularly given there's trepidation that it may be extended beyond 2028.
He went on: "The investment outlook is very mixed. The risks are quite high because of the big oil and gas price uncertainty, the fact costs are rising in general, and because of the windfall tax. There is much uncertainty."
It emerged in recent days that latest drastic proposals from Labour for Britain's offshore oil and gas sector could lead to a massive decline in the North Sea industry.
The possibility of such a devastating situation unfolding in the next few years has become apparent in speeches from leading opposition politicians.
Trade body Offshore Energies UK pulled no punches at the weekend when it responded to radical plans for the sector if Labour wins the next General Election.
Alarm at Labour plans
Earlier last week, Sir Keir Starmer had caused widespread alarm in the oil and gas sector when he vowed to halt investment in new offshore fields if Labour takes power.
The Labour leader ruled out new investment in North Sea fossil fuels as he outlined the party's mission to go green.
But things got even worse at the weekend when it emerged that Shadow Chancellor Rachel Reeves revealed that a Labour Government would make the controversial windfall levy on oil and gas producers even more draconian.
She pledged to end the fossil-fuel investment allowance, and tax oil and gas profits at the same rate as Norway - an increase of 3% to a sky-high 78%.
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