Pressure is growing on ministers to make calls to the universal credit helpline free, after it was revealed that low-income claimants could be paying up to 55p a minute for calls to fix problems with their claim. Campaigners want charges dropped as more evidence emerged of claimants being forced to spend long periods waiting on the phone to resolve issues, and often having to make a number of calls.

There are also concerns that poor training of call centre staff and underlying problems with the complex universal credit system are contributing to long waiting times.

One Department for Work and Pensions employee, who spent eight months managing a team of staff answering calls from universal credit claimants in one of the trial areas, said workers struggled to stay on top of the volume of calls, and often failed to answer queries within the required time period, causing claimants to call back to chase problems. “The work was backing up, and the calls piled up. Sometimes I felt terrified and exasperated for them, sometimes we were shrugging our shoulders. We were doing everything we could, running overtime, trying to break down the outstanding work,” he said.

Campaigners say official guidance supports switching a government helpline to a free 0800 number – which would transfer the cost of the call to the DWP – when callers are likely to be vulnerable and on low incomes.