Lorry drivers and shunters at Müller’s Stonehouse factory will strike for 11 days over a breach of rota agreement.

Some 70 workers will escalate their dispute at the factory over imposed rota changes.

The strike which started on October 19 will continue until October 29.

Union Unite says the employer is seeking to impose a change to a five days on two days off rota system to require all drivers to work at least one day every weekend.  

The move is a clear breach of an agreement the company signed with the union earlier this year, according to Unite.

The workers are responsible for delivering milk and other dairy products to M&S and Waitrose nationwide.

Unite general secretary Sharon Graham said: “It’s very simple; Müller signed an agreement with our members and they should stick to it. 

“Unite will not accept attacks on our members’ jobs, pay or conditions. Mullers’ Gloucestershire workforce has the union’s full backing in this dispute.”

The strikes will disrupt the milk supply chain for products to the site’s main customers, M&S and Waitrose. Supplies to Sainsbury’s and Tesco, which receive deliveries from the Stonehouse plant, will also be disrupted.

Unite regional officer Amy Roberts said: “Muller needs to abide by the agreement it signed and drop these rota changes, which will negatively impact our members’ quality of life.”

Stroud District Councillor Trevor Hall (Community Independents, Durlsey), who is among those who have been at the picket line in recent weeks, said he is fully behind the workers.

“I wholly support their action. The company must honour agreements that they make. They entered into an agreement with Unite over rosters earlier in the year and now they are trying to go back on that agreement. That cannot be acceptable.

“As far as I’m concerned, good on the workers for stepping up their actions and I hope they carry on until such time they get justice and win it.

A spokesperson for Müller Milk and Ingredients said: “These rota changes were implemented following consultation and agreement with joint trade unions last year.  

“The agreement aims to transition those on legacy five days working / three days off patterns to align with the five days working / two days off pattern which most full-time employees in the UK are familiar with.   

“Following the introduction of the rota changes, which are not related to pay, a small number of logistics employees at our Severnside site voted in favour of industrial action.  

“It is important to stress that we have thorough plans in place to ensure deliveries of dairy products to our customers will not be affected.”