Workers at rail industry suppliers Unipart Rail went on strike on Thursday in a dispute over union recognition.
Members of the Rail, Maritime and Transport Union (RMT) at the company’s site in Crewe walked out for the day.
The RMT said the firm has derecognised the union and was threatening disciplinary action against workers going on strike.
RMT General Secretary Mick Lynch said: “Unipart Rail’s threats to dismiss our members for exercising their democratic right to strike are an outrage and a clear attack on all workers.
“Any attempt to victimise our members for standing up for their rights will be met with the full force of RMT’s legal and industrial strength.”
Unipart has said it has ended voluntary recognition for the RMT at the Crewe site affecting a “small number” of employees and continued to have a voluntary recognition agreement with another union.
