The bin strike in Birmingham could last until December after nearly 400 workers voted to continue industrial action.

Unite, the trade union representing the striking workers, said 97% of workers voted in favour of further strike action in its latest ballot on a 75% turnout.

Unite’s general secretary, Sharon Graham, said: “Unite will not allow these workers to be financially ruined. The strikes will continue for as long as it takes. Unite calls on the decision makers to let common sense prevail in upcoming negotiations.”

Bin workers in Birmingham have been striking since January and walked out indefinitely in March in a dispute over job and pay cuts.

Piles of black bags in the streets and overflowing wheelie bins have led to an influx of rats in some parts of the city.

Huge queues have formed at mobile waste collection points as residents try to get rid of their rubbish. Police were called to shut down roads because of overwhelming crowds on one occasion.

The city council made a renewed offer to the workers last week after mediated negotiations, but Unite said it was too little and too late.

“After smearing these workers in public since January and telling them to accept a fair and reasonable offer that never existed, the council finally put a proposal in writing last week,” Graham said. “True to form, the proposal came weeks late and was not in line with the ballpark offer discussed during Acas talks in May.”

She said government commissioners brought in to oversee the running of the council after it declared itself effectively bankrupt in 2023 had “watered down the deal” despite not taking part in negotiations.

Relations between striking workers and the council have continued to deteriorate, and in recent weeks the council was granted a court order to stop waste vehicles being blocked from leaving depots by those on the picket line.

It said more than 12,000 tonnes of uncollected waste had accumulated on the streets one week in May because collections were disrupted “due to industrial action by pickets” where police had scaled down their presence.

Unite has insisted the actions of its members have always been lawful and peaceful.

The union says 170 former waste recycling and collection officers (WRCOs) and 200 drivers face losing up to £8,000 a year under the council’s current proposals, but the council has disputed this. It previously said only 17 former WRCOs could lose a maximum of £6,000 and that all have been offered alternative roles on the same pay grade.

A council spokesperson said: “This is a service that needs to be transformed to one that citizens of Birmingham deserve and the council remains committed to resolving this dispute.

“We have made a fair and reasonable offer that we have asked Unite to put to their members and we are awaiting their response.”

The council denied that its leader or the commissioners had watered down any offer, and said Unite’s ballot was not a response to its latest offer made through Acas.