Hundreds turned out in Birmingham on Saturday to march against the closure of the city's HP sauce factory.
MPs and community leaders were joined by workers for a rally at Aston Park before a march to the factory gates in nearby Aston Cross.
Factory owners Heinz plan to shift production to the Netherlands, with the loss of 125 jobs.
The Save Our Sauce campaign, launched to fight the closure plans, has been backed by politicians and unions.
Deputy general secretary of the Transport and General Workers' Union Jack Dromey said the US firm had broken promises.
"Heinz gave promises to keep production of HP in Birmingham, but those commitments are as thin as the sauce's imitations," he said.
"This march is not just about the sauce and the 125 workers whose jobs are at risk, it is about the local community, a prime British brand and keeping manufacturing jobs in the UK."
Speaking to workers at the gates of the factory building, he added: "HP is a British icon.
"The workers of HP are the sons and daughters, grandsons and granddaughters of other HP workers.
"They have worked at this factory which has put that bottle of sauce on our teatime tables for 100 years and we must ensure it's there for the next 100 years."
Martin Rodway, a worker at the factory, said: "I've done 16 years of work at HP and I want to carry on - it's as simple as that.
"It's just a little factory but if you talk to anyone they know where it is, what it does and what it means to this town. Just to shut down like that is heartbreaking."