Five Labour mayors have backed workers' right to strike amid the cost of living crisis and have urged employers to meet with trade unions.
The industrial action at the Gilmoss depot affected their entire Merseyside operation. Workers could also walk out on other dates throughout July if the dispute is not resolved.
Industrial action on the railways from RMT members brought Britain's transport network to a standstill last month; with the issues still not resolved, there could be more to come.
Part of the statement reads: “No one wants to see strikes happening. But at times, the only means working people have left to defend their livelihoods is industrial action. We support the right to take action to protect jobs, safety, pensions, pay and conditions.”
Reaction in Liverpool
We took to the streets of Liverpool to find out if you are in support.
‘You have to stand up for what you believe in’
Graham said: "It's unfortunate, and people are going to suffer from it, but I agree with them in that respect, and sometimes you have to stand up for what you believe in."
Pat said: "Total rubbish. They want to get back to work. Think of their wives, think of their children and think of what they're not putting on the table."
‘I sympathise with them’
Charles said: "They need to make a living so I sympathise with them."
Upcoming strike action
The mayors - Steve Rotheram, Andy Burnham, Nik Johnson of Cambridgeshire and Peterborough, Oliver Coppard of South Yorkshire, and North Tyne’s Jamie Driscoll - warned there could be "many more" workers from the likes of teachers, doctors and other NHS staff, who could be next to walk out.
Stagecoach Merseyside drivers, railway workers and barristers have not ruled out further strike action.
Plus, those hoping to jet off abroad this summer could potentially face travel chaos at airports as Spanish EasyJet staff and Ryanair staff are set to strike this month as part of a dispute over pay.