Hundreds of bus workers are to go on a continuous strike in a dispute over pay in the latest act of industrial action this summer from transport workers.
Engineers and drivers employed by Stagecoach Merseyside will walk-out indefinitely on 20 July, according to Unite.
They already downed tools once this month, and will also withdraw their labour on 15 and 18 July.
The 370 workers were offered a greater than 10% pay rise offer last month, according to Stagecoach, but this was rejected.
Stagecoach employees in Worthing, West Sussex, were given a 15.8% rise, according to Unite.
The country was hit by a walkout of rail staff two weeks ago, while BA staff have suspended a walkout following a "vastly improved" pay offer from the airline.
It comes as part of what some call a "summer of discontent" amid pressures from the cost of living crisis, and the aftermath of disruption from the pandemic.
Strikes are also set to talk place across the continent, including easyJet staff in Spain later this month.
'Stagecoach is a wealthy company, it can afford to pay fairly'
Stagecoach said that Unite is refusing to join negotiations through Acas, which mediates such discussions.
Speaking about the walkout in Merseyside, Unite General Secretary Sharon Graham said: "Stagecoach is a wealthy company, it can easily afford to pay fairly and Unite is determined to ensure that it does.
"Our members simply want the rate for the job and are not going to accept being underpaid a moment longer.
"Stagecoach's refusal to make an offer that would resolve this dispute has, however, resulted in an escalation in industrial action.
"Unite will be giving our members the union's complete support until they receive an acceptable pay increase."
Matt Davies, managing director of Stagecoach Merseyside, said: "We have continued to leave no stone unturned in our efforts to reach a fair settlement.
"Acas is ready and willing to support joint talks, but it is deeply frustrating that Unite has firmly blocked our olive branch.
"We remain 100% committed to reaching an agreement with Unite, but that can only be achieved by talking and with commitment and flexibility on both sides.
"It is difficult to understand how the union can in one breath recommend our above-inflation pay offer and in the next, call an all-out strike."