Analysts at Wood Mackenzie have calculated that the North Sea could still hold 14 billion barrels worth of recoverable oil and gas - three times more than previously thought.
The North Sea Transition Authority (NSTA), Ed Miliband's offshore regulator, had estimated that around four billion barrels remain.
But the figure from Wood Mackenzie, a global leader in energy data, paints a far more positive picture.
If accurate, The Telegraph reports, oil and gas reserves in the North Sea could be sufficient to cover the entirety of the UK's fossil fuel demand during the shift to net zero by 2050.
The analysis reached its 14 billion-barrel conclusion by looking at "recovery rates" and comparing North Sea fields with 35,000 others across the globe.
It said: “If UK fields were able to match recovery factors from analogous global fields, an additional 9% could be recovered. If best-in-class recovery factors were matched, an additional 18% of recovery could be added.
“These scenarios would potentially add seven and 14 billion barrels of additional production, respectively, over the lives of the 100 largest fields.”
And with the government looking to soften its position on new North Sea exploration licenses, the amount of oil and gas recoverable could be even more.
NSTA data estimates an additional 15 billion barrels could be recovered from unexplored areas outside of existing fields.
Read more in The Telegraph.