One of Britain's most powerful unions and key funder of Labour, the overwhelming favourites to form the next UK government, is stepping up a revolt against the party's oil and gas stance despite election assurances over the energy future from leader Keir Starmer.

It comes as The Herald can reveal that the party, seen as the child of the unions, has become far less reliant on them for financial support.

There is concern that Labour's vision for the transition from oil and gas in the North Sea outlined in Scotland on the election trail has failed to roll back on a bid to ban new fossil fuel project licences, despite concerns over major job losses by 2030, one of the key concerns of the Unite union.

The general secretary of Unite Sharon Graham, has told members that in the wake of Labour's energy strategy in Scotland: "Now we need to see that plan."

Unite sources say the Labour Party's transition plan was "weak" and that its rebellious 'No Ban Without a Plan' campaign in Scotland which involved diverting funds that would be expected to be used to elect a Labour government would continue and will be stepped up.

READ MORE: Union warns £6.6bn needed now to save 30,000 Scots oil and gas jobs

The party and the trade union movement have been intrinsically linked historically.

In 1899, a Trades Union Congress resolution began a chain of events that led to the establishment of the Labour Representation Committee in 1900 and the party soon after.

But Electoral Commission data seen by the Herald shows that Labour's level of reliance on unions for donations has dwindled  - dropping from £2 in every £3 the year before Labour's last General Election victory in 2005 to less than £1 in £5 before the forthcoming one.

The Herald:

Unite's campaign demands that over £6.6billion must be committed over the next six years to save over 30,000 Scots oil and gas jobs by the end of the decade.

Labour's biggest union backer is targetting six key Scottish election constituencies that are heavily dependent on oil which the Labour Party hopes to seize at a forthcoming general election, calling for the party to reconsider its current policy banning new oil drilling licences.

The campaign involves the erection of billboards, paid advertising displays, and canvassing residents.

Ms Graham has warned that the nation's oil and gas workers were heading toward becoming "the coal miners of our generation" through the loss of jobs.

She had urged Labour to become "the heroes of the hour" by committing to the union's radical investment plan which would save 30,000 jobs and create 6,000 more by the end of the decade while scrapping the proposed 'no oil and gas projects' ban.

About three-quarters of the country's 187,000 miners went on strike in 1984 and 1985 to oppose pit closures, which were expected to mean 20,000 job losses.

The union says that the "attempts" by Labour to reassure North Sea workers came after a week of intense media pressure.

Mr Starmer said that the party's green energy plans will ensure the UK’s transition away from oil and gas does not repeat mistakes from the phase-out of coal.

He argued his party's plans for a new green investment firm would safeguard replacement jobs for generations to come.

Labour wants to set up a new public company, branded Great British Energy, to be headquartered in Scotland, and it has been a feature of campaigning in Scotland.

But it has been confirmed that Mr Starmer's vision has not been enough for Unite, which is continuing its campaign to save Scottish jobs across Scotland.

A circular to Unite members from Ms Graham in the wake of Mr Starmer's vision said that the Labour leader was "forced to reassure" that we are "not turning off the taps" and that "I won't allow a transition to happen which hasn't been planned for".

But she added: "We need to see the money. We need to see the jobs."

Joe Rollin, long time Unite organiser who heads the union's community campaigns confirmed that Unite are holding back "a lot of the money" they used to give to Labour under Sharon Graham's leadership to carry out campaigns such as the 'No Ban Without a Plan'.

The Herald:

"We are affiliated but we don't give them a blank cheque anymore."

Campaign billboards have now appeared in Glasgow, Dundee, Edinburgh, Falkirk, Glasgow and Grangemouth.

Members have been more recently leafletting and gathering petition signatures in Aberdeen and Falkirk in the past week and seeking support for the displays of posters in windows.

"We have to keep pushing. We really want to push the message home to continue the work in the field," said Mr Rollin.

"There is still a long way to go because we don't have any details on the jobs yet [from Labour], so the campaign remains relevant.

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"Even though we want Labour to win the election we have to hold the party to account."

In the year before this election (2023), the Labour party pulled in £29.684m in donations of which £5.535m (18%) was from unions.

In 2018, the year before the 2019 general election in 2019, the Labour Party brought in £17.282m in donations of which £6.572m (38%) was from trade unions.

And in 2014, the year before the 2015 general election, some £7.998m (39%) out of £20.502m of Labour donations came from trade unions.

The Herald:

In 2004, the year before Labour's last election victory under the leadership of Tony Blair, more than £2 in every £3 donated was from unions. The party brought in £14.776m of which £9.94m was from trade unions.

Labour has pledged to work with the SNP government to deliver the long-awaited ‘skills passport’ for oil and gas workers as part of a bid to help protect North Sea jobs.

Shadow Scottish Secretary Ian Murray was speaking to businesses in Aberdeen on Wednesday about the plan to help transition offshore workers into renewables.

Analysts have delivered stark warnings that Labour’s proposed North Sea tax increases could destroy thousands of jobs.

Plans for a skill passport, which already has the backing of both the UK and Scottish governments, have been in the pipeline for years but have been hit by delays.

And Mr Rollin added: "We are really happy members asked for this campaign and launched it with great success because we weren't to know the following week was the election. It was launched at a fortuitous time.

"It has become one of the key areas of debate which is fantastic.

Labour wants to hand the Scottish-based energy company £8.3bn over the next five years for investments, funded by a windfall tax on the profits of oil and gas companies.

The government already has such a tax, recently extended until 2029, but Labour would charge a higher rate and close some tax allowances for investment.

The Herald has previously revealed that the oil and gas industry in Scotland has shed nearly 40% of its jobs amounting to 50,000 in Scotland over a decade, according to industry figures - while the number gained from low carbon enterprises has risen by just 2,500.

Data gathered by the trade association, Offshore Energies UK working with the multinational data analytics and consumer credit analysis Experian found that the number of jobs directly and indirectly employed in oil and gas in Scotland have crashed by nearly 40% since 2013 from 117,900 to just 74,100 in 2022. That includes 31,000 directly employed and 43,000 indirectly.

Unite's billboard campaign has hit Glasgow.

Unite gave Labour £3.5m in the run-up to the 2019 general election, making it by far the biggest single contributor to the party’s campaign. Currently, it has £29m in its political fund.

Earlier this week, opinion pollsters YouGov said Labour was set for its biggest ever victory in next month's general election, winning by a larger margin than in 1997 under former prime minister Tony Blair.

YouGov's poll predicted that the party would win 422 seats in parliament, giving them a 194-seat majority, while Prime Minister Rishi Sunak's Conservatives are on course for their lowest total in more than a century.

The Conservatives are expected to be reduced to 140 seats, according to the multi-level regression and post-stratification (MRP) poll which uses big data sets and demographic analysis to predict results in individual seats.

YouGov said it would be the biggest collapse in support for the Conservatives since 1906 and its model suggested that the party could be set for "near wipeout" in many areas, including London, the North East, the North West, and Wales.