About 250 jobs will be lost at the Walkers snacks factory in Swansea after the company confirmed it will close.
Walkers is transferring the work to other sites. The closure will be phased over the next six months and staff will be offered jobs in other plants.
The company said it was a “difficult decision”, but would mean more efficient distribution.
The Swansea site produces a wide range of Walkers products, including Wotsits, Monster Munch and Bacon Fries.
Officials from the Usdaw union said they were “disgusted” with the announcement.
“The staff are absolutely devastated by this shock news and we are disgusted that there has been absolutely no prior consultation with Usdaw before the closure was announced,” said divisional officer Nick Ireland.
“This offer to move across the country is not really an option for most for our members so we’ll be doing all we can to find them other work in the Swansea area,” he said.
The union has contacted Swansea MP Sian James to gain support for keeping the factory open.
