Hundreds of former members of the military have had their pensions slashed after receiving letters telling them to repay thousands of pounds because of a clerical error.

The Ministry of Defence (MoD) confirmed to the BBC that more than 1000 retired service personnel are being pursued for debts. The majority, 335 veterans, were overpaid a total of £5.1m as a result of incorrect National Insurance calculations.

The Forces Pension Society said it is aware of a small number of veterans whose debts were wiped after raising a formal complaint.

Ray Lawton, 70, was told in July he owed £8,000 following six years of overpayments. Days later, his monthly military pension was cut from £550 to £365.

"I haven't got £8,000 to pay out," said Lawton, who served 16 years in the Royal Artillery.

"I've got a little bit put aside but nowhere near that much."

The Portsmouth-based veteran told the BBC: "I've trusted the army all my life even when I left and I trusted my pension would be right. Then this letter comes and it's just blown it all out."

Lawton's letter was sent from a company called Equiniti, which administers the pension scheme on behalf of the MoD.

It said an error in its system meant he had been overpaid for years.

Lawton is one of many veterans from across the UK who contacted BBC Your Voice after receiving letters out of the blue seeking money they didn't know they owed.

The Forces Pension Society, a not-for-profit which supports military retirees, said it is aware of many overpayment cases running into the tens of thousands of pounds.

A small number of veterans have been told they owe six-figure sums.

The MoD confirmed errors relating to National Insurance adjustments, Pension Sharing Orders (PSO), Early Departure Payments (EDP) and State Pension Age (SPA). It says it is investigating issues on a case-by-case basis.

It added that of the 335 veterans affected by National Insurance errors, a third have paid off their debt in full and 52 have an agreed repayment plan in place. So far, of the £5.1m, £304,000 has been paid back.

Veterans said they want more clarity about the debt and how it has been calculated. Some have called for it to be wiped.

The government said it has a responsibility to recover the funds.

An MoD spokesperson told the BBC that it recognises that errors to pension payments "may cause uncertainty", adding that it is contacting veterans and "providing support for anyone who requires it".

"Where payments have been made in genuine error, we have a responsibility to recover taxpayer funds and will always seek to do so in a sensitive and proportionate way," the spokesperson added.

However, former Conservative defence secretary Penny Mordaunt, said: "While public bodies have a duty to recoup such costs if it makes financial sense to do so, no such assessment has been made in these cases.

"There is a compelling case in many instances for the debt to be wiped".

Lawton does not want the taxpayer to pick up the tab, he is happy to have his pension reduced to the level it should have been but thinks the private company should refund the bill for what he sees as their mistake.

"I think they should take responsibility for it because it's not my fault."

In Truro, Andrew Thorburn agrees.

He served 36 years in the Royal Navy and has been told he owes £26,438. As a result, his pension has been cut by around £650 per month.

"I think it's despicable that they are now saying 'yes, we've made this mistake however you're going to pay for it'. How can I forgive the government for that?"

He said: "The financial shock is absolutely devastating and it's still ongoing."

RAF veteran Barrie Goodwin contacted Equiniti six years ago after receiving a higher payment than he was expecting.

He was told the change was because he had reached state pension age. He's since been notified he was overpaid £32,188 and must hand it back.

"I checked, was told it was all correct and now have to repay it," he said. "I'm already cutting back on luxuries. I was helping one of my grandchildren through nursey – that's had to change.

"If the debt isn't waived, I will really struggle."

Equiniti told the BBC it could not discuss individual cases but recognised the concern caused to pensioners.

A spokesperson said it said it was not responsible for the decision to recoup taxpayers' money but "administration of a scheme of this scale involves multiple organisations, systems and processes over many years".

Technology company Sopra Steria has been in charge of the veterans' pension scheme since 2023, and had subcontracted the administration to Equiniti.

A Sopra Steria spokesperson told the BBC that "errors that led to incorrect pension payments originated over a decade before Sopra Steria took over the contract".

The company said it is "working closely with the MoD and Equiniti to ensure robust safeguards are in place for the long term".

The Forces Pension Society is advising anyone who receives an overpayment letter to verify its authenticity, request more information from Equiniti and using the right to complain through the Internal Disputes Procedure.

Additional reporting: Adam Clarkson and Elaine Doran