Unison argues that the staff should be paid the correct rate for the jobs they're doing, but the council is refusing to do so, leaving them with little option but to consider strike action again. The union says social worker shortages and increasing demand for services mean the role of support officers has expanded significantly. It says support staff frequently find themselves being used in place of social workers, but without receiving any additional pay.

Support workers regularly undertake far more complex tasks than previously, adds Unison.

Talks between the union and managers at the conciliation service Acas broke down last month, with Unison reps accusing the council of refusing to negotiate seriously on finding an end to the dispute.

The council staff have already taken 69 days of action since July last year. They say they don't want to keep walking out. But they do want to be paid properly for the work they do.

Unison North West regional organiser, James Rupa, said: ‘Lancashire County Council is exploiting its social care support officers. It's taking advantage of their expertise and good nature to get vital social work services on the cheap.

‘The workers are a vital lifeline for many of Lancashire's most vulnerable people. Without their visits and assessments, signs of worsening health would go unnoticed and care plans collapse.

'Staff have had enough. They don't want to take any more strike action. They just want to be paid fairly for the work they do. And they want the council to start talking seriously about how to end this long-running dispute.'

In response, a spokesman for Lancashire County Council, said: ‘We deeply value our staff and are listening to their concerns. We recently held a positive workshop with our adult social care support officers and gathered some valuable feedback, which we are now reviewing.

‘We are disappointed Unison has walked away from Acas conversations and chosen to ballot our workforce as we are constructively working with them to find a way forward. We will continue to work with our staff and the trade union to reach a positive resolution to the ongoing dispute.'

The ballot will remain open until Friday 29 August.