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Since 1964 the UK has issued 2,609 licences to look for oil and gas under its seas, and about 48 bn barrels of oil equivalent (boe) have come out. This page follows that history on the map and field by field in 3D, then asks what is left: how much more would be produced, and how much tax it would pay, if no more licences were granted, and if the unlicensed areas were opened up. The licence, field and resource data are the North Sea Transition Authority’s (NSTA), as used in my North Sea Oil and Gas Explorer; tax receipts are HMRC’s. Scroll and each chart moves on with the words; Back and Next do the same.
48 bnBarrels of oil equivalent produced so far
3.6 bnMore from 2026 with no new licences (central case)
+1.0 bnExtra if the unlicensed areas were opened up
+£8bnExtra tax from that, on top of £24bn
Sixty years of licences on the map
UK continental shelf · offshore production licences
The first round, 1964. The government divided the UK’s share of the North Sea into blocks and, in September 1964, issued 53 licences to explore 80,700 km² of it. Most of that first award sat off the east coast of England, where gas had been found across the water at Groningen.
Gas in the south. West Sole was found in 1965 and came ashore in 1967, followed by Leman, Hewett and Indefatigable. The blue shapes are gas fields in production. Purple blocks are licences in force; grey ones have already been handed back.
Oil in the north. Forties was found in 1970 and Brent in 1971, in deeper and rougher water east of Scotland and Shetland. The first oil came ashore in 1975. By the end of 1980 there were 259 licences, and the orange oil fields had overtaken the gas.
The peak, 1999. Dozens of smaller fields were tied in around the giants through the 1990s, and output reached its highest in 1999. Many of the first fields had already closed: they are the grey shapes among the coloured ones.
The most licences, 2005. Output was already falling, but new rounds kept offering acreage, much of it blocks that earlier holders had given up. At the end of 2005 there were 670 licences in force covering 130,300 km², the most there have ever been.
Today. 345 licences are in force, covering 83,700 km². The grey is everything that has been licensed at some point and given up: most of the North Sea, the Irish Sea, the waters west of Shetland and out towards Rockall. Hover over the map, or tap it, to read off a licence or a field.
What is not licensed. The green blocks are unlicensed, and the NSTA puts some oil or gas in them: discoveries nobody has developed, mapped prospects nobody has drilled, and wider estimates for whole basins. Much of it lies under blocks that were licensed before and handed back.
What came out
United Kingdom · million barrels of oil equivalent a year
Gas first. Within eight years of the first gas landing, the southern North Sea was producing over 200 million boe a year, and Britain’s homes had been converted from town gas to burn it.
Then oil, far more of it. From almost nothing in 1974, oil output passed 800 million barrels a year by 1984. It fell after the Piper Alpha disaster of 1988, which killed 167 men and led to safety work across the older platforms.
A second peak in 1999. New, smaller fields took oil back above its 1980s level while gas kept rising. Together they reached about 1.5 billion boe in 1999, over four million barrels a day.
More than the UK used, for a while. The dashed line is UK demand for oil and gas. From 1981 the UK mostly produced more than it used. Since 2005 it has used more than it produces, and the gap has widened even as demand has fallen.
A quarter of the peak. Output has fallen in most years since 1999. The licensing rounds of the 2000s and 2010s, the busiest there have been, slowed the fall for a few years after 2014 but did not reverse it.
Where it came from, field by field
The chart above adds up the whole country. The map below splits it by field. Each spike stands on a field, and its height is what that field produced in the year shown, oil and gas together; where fields sit close together their spikes add up into ridges. Orange is oil and blue is gas, mixed where a field produces both. The figures are the NSTA’s monthly returns for each field, added up by year. Scroll, or use Back and Next, and the map flies through the story. Drag it to move it, and drag with the right mouse button, or with Shift held, to turn it; on a phone, drag sideways or use two fingers.
UK offshore fields · million boe a year
Gas first, 1967 to 1974. West Sole sent the first gas ashore in 1967, and Leman, Hewett and Indefatigable followed. By 1974 five southern fields produced 202 million boe a year, Leman alone 92 million. The NSTA’s returns for gas fields are incomplete before 1990, so these spikes are striped: they are the national total, shared among the fields producing at the time by their area.
Then oil, 1975 to 1980. Forties, east of Aberdeen, began producing in 1975. In 1980 it produced 194 million boe, more than any UK field has in a year before or since. Further north, Piper, Brent and Ninian rose with it, and by 1980 oil (588 million barrels) was well over twice the gas.
Brent, 1985. The northern North Sea, between Shetland and Norway, now produced 643 million boe a year, 55% of the UK’s 1,171 million. Brent, with its gas, produced 194 million boe, a whisker below Forties’s best.
Piper Alpha, 1988. On 6 July 1988 explosions and fire destroyed the Piper Alpha platform and killed 167 men. Piper produced nothing in 1989, and with other platforms shut for safety work the UK’s output fell by 18%, from 1,108 million boe to 905 million. Oil flowed from Piper again in 1993, from a new platform.
The peak, 1999. Output reached 1.6 billion boe, from 201 fields against 43 in 1985. No field came near Forties or Brent at their height: the largest, Brent again, produced 85 million. The peak was built from many smaller fields across the Central North Sea, gas from the south and from Morecambe Bay, and the first oil from west of Shetland.
Buzzard, 2008. Found in 2001 and producing from 2007, Buzzard was the largest new field in a generation: 75 million boe in 2008, the most of any field that year. Around it output was falling fast. The UK’s total, 966 million boe, was 40% below 2000.
West of Shetland, 2019. In deep water beyond Shetland, Schiehallion came back with a new production ship and Clair grew with a second platform. In 2019 the area produced 86 million boe, 14% of the UK’s offshore output.
Today, 2025. 213 fields produced 395 million boe, a quarter of the peak. The largest, Culzean, a gas field in the Central North Sea, produced 27 million boe, a seventh of Forties in 1980.
Everything since 1967. Now each spike is a running total: all its field had produced by the end of each year, 47.6 billion boe by 2025. Brent and Forties have produced about 3 billion boe each, and Leman, the largest gas field, 1.9 billion, most of it in the striped years. The ten largest fields account for almost a third of the total, and the Central North Sea for 42%.
The map below is yours to explore. Choose each year’s output or the running total, play the years, open a region to see its fields, and click a spike or a row to see a field’s output year by year; Back and the trail above the map take you back up. Drag the map to move it, and drag with the right mouse button, or with Shift held, to turn and tilt it. Zoom with Ctrl (⌘ on a Mac) and the mouse wheel, a trackpad pinch or the + and − buttons; the compass beside them turns the map back to face north. On a phone, drag sideways or use two fingers to move, pinch, twist and tilt it. The button beside Reset fills the screen with the map, its choices and the list; Esc or the same button brings the page back.
UK offshore fields · million boe a year
What is left
The NSTA publishes an inventory of what remains, most recently for the end of 2024. It sorts the oil and gas by how sure anyone is that it exists and will be produced. Each dot below is 100 million boe.
One dot = 100 million barrels of oil equivalent
47.7 billion boe produced; up to 24.9 billion estimated to be left. The grey dots are what has come out. The coloured ones are the NSTA’s whole inventory. Purple is on licences that exist today; green is not.
Reserves, 2.9 billion boe. Oil and gas in fields that are producing or have an approved development plan. This is the only part that companies have committed the money to produce.
Found but not approved, 4.2 billion boe. Oil and gas that has been discovered on today’s licences but has no approved project: extensions to producing fields, proposed developments such as Cambo, and small discoveries. Some will be developed; much has been known about for decades and never has been.
Prospects on licences, 1.5 billion boe. Mapped structures on today’s licences that nobody has drilled. The volume already allows for the chance that a well finds nothing, so it is an average over many prospects, not a count of barrels.
Outside licences: found and mapped, 5.1 billion boe. Small discoveries (2.0 billion) and undrilled prospects (3.1 billion) under blocks nobody holds. None of this can be produced without a new licence.
Unmapped plays, 11.2 billion boe. The NSTA’s estimate of what whole geological regions might hold beyond anything mapped, mostly west of Shetland and in the Rockall Trough. It is the largest and by far the least certain part.
From most certain to least. The less certain a category, the larger it tends to be. Of the 24.9 billion boe, 8.6 billion is on today’s licences and 16.3 billion would need new ones, and only 2.9 billion is in an approved project.
Two paths from here
How much of the inventory is produced depends on prices, costs, tax and geology, so this is a scenario, not a forecast. I take a share of each category: all the reserves, 30% of what has been found in and around fields, 5% of the small discoveries, 10% of the mapped prospects and 5% of the unmapped plays. With no new licences, only the categories on today’s licences count. Opened up, the unlicensed ones are added, with first output in 2032. A high case uses larger shares.
United Kingdom · million barrels of oil equivalent a year
No new licences: 3.6 bn boe more. Today’s licences carry on. Output falls by about a tenth a year, a little faster than it has on average since 2020, because the fields that remain are old and small. Gas falls faster than oil: there is less of it left in approved projects.
Opened up: 1.0 bn boe more than that. A new round takes time: the NSTA’s average from licence to first output is about five years. So nothing changes before the early 2030s, and the extra output peaks at about 50 million boe a year around 2040.
A high case. The dashed lines assume much more of each category is produced: 4.5 bn boe with no new licences and 2.3 bn more if opened up. That is close to what the industry’s trade body says is possible with its preferred licensing and tax policies.
Against sixty years of output. Either way the North Sea is in its last tenth. Opening up changes the size of the tail after 2032, but not its direction: in the central case output in 2040 is still about a third of today’s.
The tax it paid, and could pay
United Kingdom · £ billion a year, 2025-26 prices
The 1980s. With oil output and prices both high, and Petroleum Revenue Tax taking most of the profit of the big fields, the Treasury received over £40 billion a year in today’s money in the mid-1980s. Since 1968 the total is £484bn.
The 2000s and the 2010s. High prices brought a second, smaller peak. Then the 2014 price fall, lower tax rates and repayments for the cost of removing old platforms took receipts below zero in 2015-16 and 2016-17.
The windfall levy. When gas prices surged in 2022 the government added the Energy Profits Levy, taking the headline rate from 40% to 65%, then 75% and 78%. The levy has raised about £12 billion in four years. Receipts in 2025-26 were £4.3 billion.
No new licences: £24bn more. The model applies current law to the output above at $68 a barrel and 80p a therm: 40% of profit, plus the 38% levy until March 2030. Tax falls faster than output, because the levy ends and because companies reclaim tax as they pay to remove platforms.
Opened up: £8.2bn more than that. The extra output arrives after the levy has gone, so it is taxed at 40% of profit: about £8 for each extra barrel. The extra tax peaks at about £0.4 billion a year around 2040.
The high case. With the larger shares, no new licences brings £33bn and opening up adds £19bn, spread over forty years. Price matters more than either: the table below repeats the sums at three price paths.
Modelled, 2026 to 2075 · constant 2026 moneyOil and gas produced and tax paid on each path, by case and price path
The rows in bold are the ones the charts use. "High prices, then easing" starts at $115 a barrel and 240p a therm and is the North Sea explorer's default. Tax is after relief for decommissioning (£16 billion, the same on both paths). At $115 and 240p held for ever, the revenue charge announced to follow the levy also applies. Scroll sideways on a phone.
How it works
The map. Every offshore production licence block the NSTA records, with the months it was in force, drawn for each year. When part of a block is given up the rest is recorded again, so a licence can appear as several shapes over its life. Counts are of distinct licences in force at the end of each year (2026: to the latest data). Fields are the NSTA’s outlines, shown from their first to their last year of production; six fields that never produced are left out.
Output. Production and demand to 2024 are the Energy Institute’s Statistical Review series (via Our World in Data), converted at 1.70 TWh per million boe; demand includes fuel for international flights and shipping. 2025 is the NSTA’s field returns, scaled to the same basis. Each year’s total is plotted at mid-year.
Field by field. The NSTA’s PPRS returns of each offshore field’s monthly oil, condensate and gas, added up by calendar year, with gas injected back into a field taken off (a field that injected more than it produced in a year counts as producing none that year). Oil and condensate are converted at 6.29 barrels a cubic metre and gas at 5,800 cubic feet a boe, as in the explorer. Gas is measured as it leaves the fields, before what is used on platforms or flared, so these totals run a few per cent above the national figures in the chart of output; on this measure 2000 (1,618 million boe) edges out 1999 (1,610 million). Each field stands at the middle of its reporting points. Its spike is 30 km across at the foot and as tall as the field’s output that year, so where feet overlap the heights add and a cluster of fields becomes a ridge. Each year’s output stands at mid-year, and the map moves smoothly between years. The running total adds up each field’s output to the end of the year shown: across all the fields it comes to 47.2 billion boe by the end of 2024, against the NSTA’s 47.7 billion, and 47.6 billion by the end of 2025. The returns for gas fields are incomplete before 1990: Leman, the largest southern field, first appears in 1987, and Frigg in 1984. So for 1967 to 1989 the gas fields’ output is the UK’s gas production (Energy Institute) less the gas from oil fields (70% of which reached the national figure in the 1990s), shared among the gas fields in production each year, by the NSTA’s dates, in proportion to their area. Frigg, which the NSTA dates from 1984, is counted from 1977, when its gas first came ashore at St Fergus. These years are striped on the maps. The estimate gets the total right, but the split between the southern fields is only a guide.
What is left. The NSTA’s Reserves and Resources report for the end of 2024: 2.9 billion boe of reserves, 6.2 billion of contingent resources (found, no approved project), 4.6 billion of mapped prospects and 11.2 billion in unmapped plays. The split between licensed and unlicensed acreage, and between oil and gas, follows the explorer, which reads some of it from the report’s charts, so the parts are approximate. The 47.7 billion boe produced is the NSTA’s figure to the end of 2024.
The two paths. The shares of each category are my assumptions, chosen so that the cases span published projections. The central case with no new licences (3.6 billion boe from 2026) matches the top of the NSTA’s February 2026 projection to 2050, which ranges from 2.85 billion boe for existing fields to 3.63 billion with new drilling. The high case opened up (6.8 billion boe) is close to the 7 to 7.5 billion that Offshore Energies UK and Westwood say is possible with policy changes. Output on today’s licences falls by a constant fraction each year from its 2025 level, oil and gas separately, so that it adds up to the volume by 2075. Output from newly licensed areas starts in 2032 (a round in 2027 plus the NSTA’s five-year average to first output), rises for five years, holds for five and then falls 8% a year. The page takes “no new licences” literally. The government’s Transitional Energy Certificates, which allow production next to existing fields without a new exploration licence, could let through some of what I count as needing one. Licences that expire are not modelled.
Tax. HMRC’s net receipts from oil and gas production by financial year, put into 2025-26 prices with the GDP deflator and plotted at the middle of the financial year. Modelled tax uses the explorer’s tax model: 30% ring-fence corporation tax and the 10% supplementary charge on profit, the 38% Energy Profits Levy to 31 March 2030, then the announced 35% charge on revenue above $90 a barrel and 90p a therm. Costs are £18 a boe to operate and £11 a boe of investment, at $1.33 to the pound. Decommissioning relief is 40% of £40 billion, spread evenly to 2060. The model is a simplification: it has no company tax positions, losses carried forward, other allowances or payment timing, and it charges investment as output is produced rather than years before. The charts use a flat $68 a barrel and 80p a therm because that path meets the latest receipts; modelled 2026 tax is £5.2 billion against £4.3 billion received in 2025-26.
What it leaves out. The cost to the climate of burning the oil and gas, the effect on imports and jobs, and whether companies would bid for the acreage at all. More tax from one path is not by itself a reason to choose it.
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