Britain's proven and probable oil and gas reserves have decreased to 2.5 billion barrels of oil equivalent (Bboe) by the end of 2025. This amount is 0.4 billion barrels less than the previous year and indicates a reduction in the country's reserves due to the lack of drilling new exploratory wells.
Production and Field Activities
Oil and gas production in Britain in 2025 was about 380 million barrels of oil equivalent, achieved through existing field activities and performance improvements. However, this production has not been able to compensate for the decline in reserves. No new field development plans were approved this year, and only one change in the existing field development plan was approved. Producing fields managed to increase reserves by a net of 40 million barrels of oil equivalent through in-field activities and performance improvements. This increase was achieved despite declines due to downward revisions and early cessation of production in some fields, indicating a positive reserve replacement ratio of +10 percent.
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Lack of Exploratory Well Drilling
No new exploratory wells were drilled in Britain's offshore platforms in 2025. This lack of exploratory activity could lead to further declines in reserves in the future. Additionally, the estimate of probable resources has increased by 0.3 billion barrels to 6.5 billion barrels, as operators are advancing no proposed new developments and have revised existing estimates for current fields. In this case, producing fields include 1.5 billion barrels, proposed new developments 1.6 billion barrels, licensed marginal discoveries 1.3 billion barrels, and unlicensed marginal discoveries 2.1 billion barrels.
The average estimate of licensed probable resources in mapping regions and prospects has decreased to 1.2 billion barrels, down from 1.5 billion barrels the previous year, and another 3.6 billion barrels are estimated to be unlicensed. Furthermore, it is estimated that there are 11.2 billion barrels of additional unlicensed probable resources in fields outside mapping regions and prospects.
Discovered reserves and resources are approximately 70 percent oil and 30 percent gas in oil equivalent. By the end of 2025, Britain has produced about 48.1 billion barrels of oil equivalent.
The regulator also reminded that the reserves of developments affected by the session court ruling, which revoked their approvals, are still classified as reserves by operators. Licensees can continue development work, but no oil or gas can be produced while the approval decision is pending. The reserve and resource statistics for the fields are based on operator data and have not been verified by NSTA.
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