THOUSANDS of shipyard workers yesterday learned their jobs may be under threat as union leaders hit out at a “total betrayal” of the workforce.

GMB Scotland yesterday vowed to fight the “worst-case scenario” of 800 job losses on the Clyde after news of a potential government pull-back on frigate orders was leaked.

Senior officials met with yard operators BAE Systems on Thursday and planned to inform workers at mass meetings on Monday.

However, urgent meetings were held with key figures yesterday, while messages were sent to all members, after news of possible changes to a vital Ministry of Defence (MoD) order appeared online.

First floated in 2014, the multi-million pound plan for the construction of 13 Type-26 frigates was last year reduced to eight, with work also pushed back to 2017.

Now, the union has learned that further changes could see up to one-fifth of all work outsourced to yards in England, leading to “significant” Scottish job cuts.

Yesterday, the MoD did not deny work could be shifted south of the border as part of spending cuts.

GMB Scotland secretary Gary Smith said this would be a “total betrayal” of workers and union officer Gary Cook accused the Tory government of playing politics with shipbuilding jobs, telling The National: “We have been let down, we have been betrayed, we have been deceived.”

Much was made of potential dangers to the yards by pro-union campaigners who warned leaving the UK would mean forfeiting the defence orders they depend on.

Cook said: “The frigate order was a massive piece of work.

“It would give us a rate of work and a volume of work that would allow us to go into the export market. We would become competitive globally.

“It was all in the run-up to the referendum, where ship workers campaigned very hard to remain part of the UK. We believe we have been lied to. We are not prepared to accept one more compulsory redundancy.”

Sheds at the yards have been cleared to make way for the building of a “car factory-style” frigate factory in order to complete the work, allowing construction on up to five vessels to take place simultaneously.

However, it is understood that this has been shelved.

Nicola Sturgeon called the news “deeply troubling”, saying: “It would be unacceptable for the UK Government to renege on its commitment to build these ships on the Clyde. The workforce at BAE in Glasgow is second to none and the promises made to them must be honoured.

“We will be pursuing these reports thoroughly and offering all our support to the workforce and to BAE systems to ensure that the contracts are delivered in full.”

A spokesperson for BAE Systems said it is “working with the Ministry of Defence to agree a revised baseline” and updated production schedule, adding: “We are engaging our trades unions as we work through this process. Our focus is to deliver the capability the Royal Navy needs, while ensuring the best value for UK taxpayers.”

Meanwhile, an MoD spokesperson said: “The Government is committed to building ships on the Clyde and to the Type-26 programme. Over the next decade, we will spend around £8 billion on Royal Navy warships.

“As set out in the Strategic Defence and Security Review, we will build two new offshore patrol vessels on the Clyde, maintaining Scottish shipbuilding capability ahead of the start of the Type-26 build.

“We will also consult with industry and trade unions as part of the national shipbuilding strategy, which will set the UK industry on a sustainable footing for the future.”

Parliamentary Under-Secretary Julian Brazier recently said it is “too early to commit to a decision” on the building of frigates on the Clyde.

In a joint statement, MPs Chris Stephens and Carol Monaghan, whose constituencies include the affected yards, said: “When the Clyde has the most skilled and experienced shipbuilders in the world, there is clearly nowhere else for these specialised ships to be built.

“The UK Government need to stop delaying and get on with awarding the contracts to our yards.

“Workers and the trade unions on the Clyde have every right to feel betrayed by these delays and we agree that compulsory redundancies are unacceptable.”