The UK's biggest unions have warned Sir Keir Starmer that his government's plans to ban new licences for oil and gas in the UK puts more than 30,000 jobs at threat.
Delegates at the National Trade Union Centre (TUC) Congress voted to support a plan calling for no ban to be implemented, until a fully funded plan is devised to guarantee comparable jobs for all North Sea workers.
Meanwhile, the government is warning of a "grim" September with up to 6,000 jobs across the steel and oil refining industries set to be cut, including 400 at Grangemouth.
Unite warns of 'false promises'
The motion was brought to congress by Unite and GMB - the countries second and third biggest unions.
It said fossil fuels should not be abandoned until workers knew how their jobs would be protected.
The move heaps more pressure on Sir Keir and his government, which is set to vote to cut the winter fuel payment received by as many as 10 million pensioners.
But Unite's Cliff Bowen, who sits on the union's executive council, said the future of oil and gas would be "the biggest test of Sir Keir Starmer's mettle".
Mr Bowen also warned of "false promises of green jobs which never seem to materialise".
He added: "Environmental action is required but exporting jobs, skills and destroying working class kids’ futures, while moving production abroad, is just burying our heads in the sand."
Union's have been long warning Labour of the damage its plans would do to the UK North Sea.
In the run up to the general election, Unite published an open letter which urged Labour to rethink its ban.
At the time, the union's general secretary Sharon Graham said: "Until Labour has a concrete plan for replacing North Sea jobs and ensuring energy security, the ban on new oil and gas exploration licenses should not go ahead.
"Labour must not allow oil and gas workers to become this generation's coal miners. Scotland's oil and gas communities are crying out for a secure future and that is what Labour must deliver."
Government 'committed' to North Sea
A Department for Energy Security and Net Zero spokesperson said: "The government has a non-negotiable commitment to securing a proud future for the North Sea.
"This includes setting up Great British Energy, a publicly owned energy company headquartered in Scotland, which will invest in technologies that will make us a world-leader in industries that use the expertise of North Sea workers such as floating offshore wind and carbon capture and storage."
Last week, it was widely reported that GB Energy would be headquartered in Aberdeen, though the government is still yet to confirm that more than two months on from the general election.
It's understood that an announcement could be made in the coming days and weeks, though the party confirmed it would be headquartered in Scotland.