900 jobs are to be lost due to the closure of a Kerry Foods plant in the English town of Burton-on-Trent.
Unions officials have described the planned closure as a "crushing blow".
Unite said it would leave no stone unturned in helping its members affected by the announcement, and has already been in touch with brewer Molson Coors, the town's second largest employer, regarding employment opportunities.
Regional officer Rick Coyle said: "This is a calamity for Burton as Kerry Foods is the town's biggest employer.
"It is heartbreaking for the workforce, their families and, more widely, a crushing blow for the regional economy.
"This is a very sad day for Burton and the end of an era."
Unite said the closure was a result of Kerry Foods losing its contract to supply supermarket giant Tesco with ready-made meals.
Mr Coyle added: "The problem going forward is that there are not that many well-paid jobs in Burton and the vicinity to replace those that will be lost at the end of August.
"We have been in touch with Molson Coors to explore employment opportunities there. Also, we will help arrange a jobs fair at the site and assist our members with their CVs and advice on updating their skills."
The union said its staff will meet management on Friday to discuss an enhanced redundancy package for its members.