Tram workers in Sheffield plan an all-out strike from Monday after bosses refused to deal with a union rep.
Any strike could bring the city’s Supertram network to a halt, affecting the 36,000 people who use it each day.
Stagecoach, which owns the network, has derecognised Unite union branch secretary Mick Fletcher.
It said he did not meet the “standards expected of a trade union representative” and “undermined the democratic voting process”.
But union members voted by almost two to one to strike in support of their union rep.
Phil Bown, a Unite regional official, said, “The company don’t have the right to dictate to the union who represents the membership. We have elections for that.”
Management’s attacks on the union follow a pay dispute last year, when members were threatening to strike over a pay freeze.
The workers were due to vote on a new pay deal, though some were worried that bonuses would be cut to finance it.
Mick Fletcher put a message on the union notice board saying that there was “very little chance of bonus payments being made”.
Management said that this did not reflect the nature of the meetings taking place and would affect the vote on the pay deal.
The notice was then replaced.
Workers voted to accept the deal, but management then derecognised Fletcher.
Unite accuses Stagecoach of breaking employment law, and a tribunal is set for later this year on the case.
Bosses are planning a contingency tram service and replacement buses to try to undermine the action.