A Walkers crisps factory is facing closure, putting 380 jobs under threat.
Under the plan, production at the plant in Peterlee, County Durham would be moved to other sites in the UK, owner PepsiCo said.
It said the decision had been taken in an effort to find "crucial savings" and to ensure the long-term growth of the business.
Manufacturing managing director at the Peterlee site, Tracey Foster, said union consultations had begun.
In a statement, she said: "In order to improve the efficiency of our UK snacks manufacturing operations, we are proposing the closure of our factory at Peterlee.
"Crisps currently produced at the site would be manufactured at our other facilities in the UK.
"Peterlee has been an important site for our business but the changes we are proposing present significant productivity and efficiency savings crucial for ensuring the long-term sustainable growth of our business in the UK.
"We appreciate this is upsetting news for everyone at the Peterlee site.
"No decisions will be made without first consulting employees and their representatives. We would also like to reassure colleagues that we will be providing on-going support and assistance from this point onwards."
Labour MP Grahame Morris, whose Easington constituency includes the Peterlee factory, described the announcement as a "bitter blow" for East Durham.