Rail workers on London Midland Trains, which serves Northampton, are to be balloted for strikes in a row over the sacking of a colleague.
Members of the Rail, Maritime and Transport (RMT) union at London Midland will vote on whether to launch a campaign of industrial action.
The union claimed its member James Crabtree, who worked as a revenue protection officer, was sacked for resisting an assault by a known troublemaker.
RMT general secretary Bob Crow said: “London Midland display posters at their stations stipulating ‘We always prosecute those who intimidate and abuse or assault our staff’, yet the company has failed miserably in their duty of care and support towards James Crabtree.
“Instead of protecting him, the company has dismissed him in the most blatant travesty of workplace justice - siding instead with a known troublemaker who is the kind of menace who should be barred from our railways.”
A London Midland spokesman said: “We are still following the disciplinary procedure which is agreed with the RMT. This is a fair process and as this case is still subject to an appeal hearing we are unable to comment on any detail at this time.
“However, we are very disappointed that the RMT have chosen to ballot their members while the agreed process is still ongoing. “
Last week the Government announced London Midland’s franchise to run trains from London Euston to Birmingham, serving thousands of rail commuters out of Northampton every week, would be extended until at least June 2017.