The head teachers’ union has demanded action from the Department for Education (DfE) to address what it describes as the “failing” Teachers’ Pension Scheme.

The National Association of Head Teachers (NAHT) said there was a litany of problems with the scheme, which has two million members, including payment delays that have left many in financial disarray.

The union told BBC Radio 4’s Money Box it was “shocked” at the number of members contacting it for help.

The DfE said it understood the problems had caused frustration and it was continuing to work closely with the scheme to resolve the issues as soon as possible.

With members across England and Wales, the Teachers’ Pension Scheme is one of the largest retirement schemes in the UK.

Although day-to-day operations are outsourced to Capita, the DfE has overall responsibility for the scheme.

But in a letter seen by Money Box the NAHT said it had “serious concerns” about how it was being run, including significant delays for members being paid their pensions.

The letter also cited excessive waiting times for members trying to get through on the phone, poor communication from pension scheme staff, and unanswered and unresolved queries and complaints.

Describing its members as “deeply dissatisfied”, the union’s assistant general secretary James Bowen said it was clear the Teachers’ Pension Scheme was failing teachers and school leaders.

“It’s just frankly not good enough,” he said, adding that the department and the pension scheme needed to “get to grips” with the problems and accelerate resolving some of the queries.

“I think we need to see some strong leadership within the Department for Education and within the Teachers’ Pension Scheme,” he said.

“Probably the only other solution is to put some more capacity into that team so it can cope with the demand that appears, at the moment, to be overwhelming them.”

After a 40-year career in education, starting as a nursery assistant before working her way up to head teacher of a primary school, Joanne Hurst has spent the last two years meticulously planning for her retirement.

She was due a lump sum pension payment on 1 September, which she had arranged to use to pay off her mortgage on that day. She was also expecting the first of her monthly pension payments in the middle of the month, but she has not seen a penny of either.

Ms Hurst said this has had “a huge impact” on her financially, costing her in lost interest and forcing her to pull money from other places to get by.

“That’s then had an impact on my mental health and well-being because I’m worried about when will this money come through,” she told the BBC.

She said trying to get answers out of the pension scheme had compounded her stress.

“Each time I ring Teachers’ Pensions I’m given different advice, conflicting advice,” she said.

“I think it’s diabolical. I think it’s grossly unfair for people who’ve worked all their lives [and] paid into a system.

“It’s not a charity, it’s something we are owed because we have paid into it.”

The NAHT’s Mr Bowen said he believed a lot of the problems stemmed from a legal judgement in 2018, which found that younger members of government schemes were effectively discriminated against.

That judgement led to the government changing public service pension schemes, including the way pension valuations were calculated.

In March, Teachers’ Pensions – which runs the Teachers’ Pension Scheme – said it had been waiting for that government guidance, and it had taken “a long time to agree for consistency [across all public service pension schemes] and to ensure calculations don’t need to be revisited”.

Mr Bowen said: “I’ve no doubt that is a huge part of [these delays] but I don’t think it explains it all.

“I think probably there is also a shortage of capacity there as well and those two things combined are probably creating the situation we find ourselves in now.”

In a statement, the DfE said: “We understand that this has caused frustration and are continuing to work closely with Teachers’ Pensions to resolve this issue as soon as possible,” adding that people can check the TPS website for updates.

Capita apologised for the delays and said active discussions were continuing to address the increase in the number of enquiries being made to Teachers’ Pensions.