In frigid waters 110 miles east of Aberdeen, a discovery was made that changed Scottish politics forever.
BP struck “black gold” in the Forties oil field in the North Sea in October 1970 - the first major finding of crude in the region.
Less than four years later, the SNP emblazoned “It’s Scotland’s Oil” across posters as they wasted little time in staking their claim on the vast reserves. The nationalists’ breakout performances in the two 1974 general elections then became the economic blueprint for the 2014 independence vote.
But since the defeat that year, Nicola Sturgeon has ditched what was once fertile ground for the nationalists, over climate concerns, as she eyes another referendum in October 2023.
Even as Vladimir Putin’s war transforms the global energy landscape, the First Minister has been resolute in insisting that ramping up North Sea production is not the solution to the current supply crisis.
However, as the conflict in Ukraine drags into a war of attrition, and oil prices surge, pressure is growing for a more balanced approach - not least from within her own party.
Fergus Ewing, SNP MSP and former Scottish energy minister, says: “There's a very strong case indeed for continuing domestic production.
“Oil and gas does supply around two-thirds of our overall energy needs… the reality is that we will continue to need and rely upon oil and gas for some considerable time to come over what is called the ‘Just Transition’.”
Ewing argues North Sea production can bolster energy security, generate it in a cleaner way than rivals in the Middle East and provide a base source for when the wind is not blowing and the sun is not shining.
Economists also say that current oil prices of more than $100 (£83) per barrel will transform Scotland’s theoretical deficit in the run-up to the proposed referendum, potentially turning Sturgeon’s Achilles heel into a positive, if only briefly.
However, under Sturgeon’s leadership the SNP has become more hostile to what was once the crown jewels in its case for independence.
It culminated in the First Minister voicing her opposition to the Cambo oil field last year in the run-up to the COP26 climate conference in Glasgow. Shell - which had a 30pc interest in the huge field - later pulled out of the project with the company said to be frustrated by the lack of political support, including from Westminster. An industry source says Sturgeon’s Cambo decision was noted in the boardrooms of oil and gas firms.
In March, Sturgeon then said production in the North Sea in the short-term is not a “practically deliverable solution” after calls mounted for output to increase, as Russian troops stormed Ukraine.
“If we were to give the go-ahead to Cambo for example right now, 2026 would be the earliest it could start producing oil,” she said.
Instead, she argued, the solution is in accelerating the transition to renewable energy sources. Her coalition government relies on the Scottish Greens.
The industry has decided not to take sides in the independence debate.
Yet Offshore Energies UK’s (OEUK) Jenny Stanning says “companies considering any major investment look very carefully at the political and fiscal landscape”.
“That is why OEUK will continue to urge both governments and all parties to champion this industry’s role in protecting energy security and achieving net zero with energy and tax policies that support investment. That will remain the case regardless of any constitutional debates or change.”
Critics of the Scottish Government’s more hostile stance to the industry say the war has transformed the North Sea debate.
Liam Kerr, Conservative MSP and shadow cabinet secretary for net zero, energy and transport, says Holyrood has “set its face pretty much against the North Sea”.
“The Scottish Government needs to take a more mature approach to the energy mix,” he says.
“I think a large part of it is a function of having the Greens in government… Part of the failure of the SNP-Green government is to look maturely at the energy mix in terms of things like nuclear baseload. This is a clear point of difference with what the UK Government is doing.”
Kerr says the opposition risks making the UK “ever more dependent on places like Qatar or Russia or Saudi [Arabia] which is just in my view a very, very dangerous and naive place to be”.
Ewing adds that a thriving oil and gas sector is needed to “preserve the skill base” for new green technologies, such as carbon capture and storage.
“You cannot pluck people from a bus stop and get them to do these jobs.”
The industry has not given up on persuading the SNP to support North Sea oil.
With the energy security issue soaring up the political agenda, sources say the oil industry has stepped up lobbying efforts in both Westminster and Holyrood, including meetings with Scottish finance secretary Kate Forbes.
Some in the industry have taken heart from the SNP’s more nuanced stance on the windfall tax, with UK energy firms set to pay an additional 25pc levy for the next 12 months.
The party was sceptical of a tax that targeted just one industry and said it should apply to all companies enjoying high profits.
It meant that “Scottish industry is carrying a disproportionate burden of funding what is a UK-wide response”, Sturgeon said.
A Scottish government spokesman says its “position is clear that unlimited extraction of fossil fuels is not consistent with our climate obligations.
“We are equally clear that the oil and gas sector plays an important role in our economy.”
They add that Holyrood is “undertaking in-depth analysis work to better understand Scotland’s energy requirements as we transition to net zero”.
By the time of the proposed independence vote in autumn 2023, Sturgeon may be persuaded to offer more full-throated support by a far rosier picture on oil and gas revenues.
Ironically, Sturgeon is turning cold on North Sea oil just at a time when it could bolster her economic case for independence.
Oil prices were just below $100 per barrel when the first independence referendum was held in 2014. Since then they have crashed, recovered, and turned negative at one point in the early days of the pandemic before soaring once more in 2022.
Brent crude, the UK benchmark oil price, has been above $100 per barrel almost continuously since the first half of April. While motorists have felt the pinch from prices at the pumps soaring to record highs, the oil surge is a boon for the Exchequer.
Government tax revenue from the oil and gas industry was just £600m in 2020-21 and £3.1bn last year. The Office for Budget Responsibility in March estimated it will hit £7.8bn in 2022-23 and £5bn the following year.
With the windfall tax on oil and gas producers expected to generate an extra £5bn, the projections suggest almost £13bn will be generated from the industry this year.
If such high prices were maintained for a sustained period, it would be transformative for Scotland’s national public finances, new estimates from the Institute for Fiscal Studies (IFS) reveal.
Official figures suggest Scotland’s notional deficit, including North Sea revenue, was 8.8pc of GDP in 2019-20, levels economists believe would be unsustainable. The UK’s deficit that year was just 2.6pc of GDP. The figures indicate an independent Scotland would need to turn to hefty tax hikes or austerity to stop the debt running out of control.
However, David Phillips, economist at the IFS, says a referendum in October 2023 would follow on from 2022-23 figures that “will likely show a very much improved relative fiscal position for Scotland”.
“It may show an implicit Scottish deficit that is lower than the UK-wide deficit this year,” he says. “That would require Scottish oil revenues of about £14bn a year.”
If oil tax revenues remained at high levels until the late 2020s, an independent Scotland “may be able to at least postpone tax rises or spending cuts” to shore up the public finances, says Phillips.
However, the volatile global geopolitical backdrop can change quickly and with it energy prices. Relying on oil revenues to prop up spending is still a risky strategy for any government to take.
Former SNP leader Alex Salmond made the figures from his 2014 independence bid add up by assuming an average oil price of just above $110 per barrel.
But Brent crude has averaged just above $60 per barrel in the near-eight years since the referendum - a shortfall that would have left a big blackhole in an independent Scotland’s public finances.
Booming North Sea oil revenues will arrive just in time for Sturgeon’s latest independence bid, but whether they will last is another question.