More than a quarter of public sector workers in Yorkshire regularly undertake unpaid overtime, figures have revealed.

Research by the GMB union show that 153,555 public sector workers in the region regularly do unpaid overtime – clocking up an average of 7.7 hours extra work a week. And 29,423 of them – 5% of the total public sector workforce in the region – put in 15 hours or more a week on top of their paid working hours.

Figures also show that 11.9% of private sector workers regularly work extra hours for no extra pay.

The research, based on the latest official statistics, showed that public sector workers in Yorkshire are “gifting” their employers £835.88m a year in unpaid overtime. The average unpaid contribution equates to £5,444 per worker or almost a quarter of annual salary.

Four out of 10 midwives and social workers are typically putting in unpaid hours. Other jobs with a high level fo unpaid overtime include teaching assistants, school secretaries, nurses, librarians and police and community support officers .

A GMB spokesman said the dedication of public sector working above and beyond their contracted hours had been rewarded by he government with “crippling” real-terms pay cuts, adding: “It’s time to tackle ever rising workloads and give our public sector workers the real pay rises they desperately need and deserve.”