Bosses at food firm Cranswick were warned today that they face further strikes at their Hull plant unless they stop trying to force inferior terms on their workers.
GMB said Cranswick had told the union's 80 members at the meat processing plant that it was going to scrap their contracts and replace them with "far inferior terms."
The workers went on strike on Wednesday and more could be held on September 6 and 7 unless the bosses listen.
GMB says the new terms and conditions would lop more than a fifth off their members' pay, on top of an eight-year-long wage freeze during which time inflation has gone up 42 per cent.
Cranswick has contracts with Simply Sausages, Weight Watchers, Jamie Oliver and Reggae Reggae.
GMB regional officer Dave Oglesby said the union was seeking "meaningful talks" with the company.
A government guided by common sense would respond to news that publicly owned Royal Mail has increased profits to £403 million by scrapping plans to flog off the service.