Conservative councillors in Leeds have called for an “urgent review” of issues within the city’s children’s services, which has seen nearly 50 social workers depart this year.

Social workers have lodged a grievance with council bosses over their workloads, the trade union UNISON confirmed on Wednesday.

The council refused to comment on the grievance when the issue was raised at a scrutiny meeting earlier this month, amid claims overworked staff feel unable to guarantee the safety of some of the city’s most vulnerable children.

But speaking at a full council meeting on Wednesday afternoon, executive member for children and families, Councillor Fiona Venner, admitted staff had expressed concerns over their caseloads.

She promised a report on the matter would be published soon, but suggested workloads and high turnover within the service were due to the underfunding of social work nationally.

Coun Venner also pointed to Ofsted’s recent grading of Leeds’ children’s services as ‘outstanding’.

But Conservative Opposition leader, Councillor Andrew Carter, said he wanted “answers” over issues within the service.

He said: “I’m now informed of multiple grievances made by frontline social workers regarding their ability to assure the safeguarding of children.

“History has shown what happens when local authorities use their Ofsted judgement as a shield and a suit of armour.”