Confectionery giant Nestle is planning to cut almost 300 jobs in the UK while moving the production of one of its biggest biscuit brands abroad.
The firm confirmed it will move production of the Blue Riband chocolate biscuit to Poland.
The GMB union has called on the government to take action over a move that will mainly hit workers in York and Newcastle, saying the firm should "be exporting chocolate and not jobs".
GMB general secretary Tim Roache called for the government to act as he lambasted the move.
"To shift the production of an iconic British brand like Blue Riband to Poland is completely unacceptable," Mr Roache said.
"Nestle are throwing people's lives, and those of their families, into turmoil for the sake of increasing profit margins.
"These factories should be exporting chocolate - not people's jobs. The Government needs to step in before it's too late and reassure millions of workers across the country this is not just the tip of the Brexit iceberg."
Nestle said it expected the loss of 298 jobs would be achieved through "voluntary redundancies" as it confirmed a 45-day consultation period with trade unions and employee reps will begin shortly.
"Nestle UK appreciates that this is an uncertain time for employees and will work hard to ensure all are supported through this difficult period," it said in a statement.
The firm said the transfer of Blue Riband production from Fawdon to a Nestle factory in Poland would "simplify and focus Fawdon's operation".
It added: "These proposals are being made by Nestle UK to ensure that these sites operate more efficiently and remain competitive in a rapidly changing external environment."