A former subpostmistress said the stress of dealing with the Post Office’s faulty IT system “nearly killed” her after it repeatedly caused shortfalls in her accounts, an inquiry has heard.

Wendy Martin, who opened her own Post Office in York in February 2015, said she immediately started facing problems with the computer systems, including transactions disappearing.

More than 700 subpostmasters and subpostmistresses (SPMs) were prosecuted between 2000 and 2014, based on information from the Horizon IT system, installed and maintained by Fujitsu.

But in December 2019, a High Court judge ruled that Horizon contained a number of “bugs, errors and defects” and there was a “material risk” that shortfalls in Post Office branch accounts were caused by the system.

Ms Martin, who encountered shortfalls but was never prosecuted, told an inquiry into the scandal on Thursday that she was forced to close her branch after just 20 months due to stress caused by the issues with the IT system.

The former subpostmistress said she had borrowed £22,000 from the bank as well as money from her family and used her savings to open the business.

But the computers immediately started to crash on a daily basis with connection constantly dropping out and transactions going missing, the inquiry was told.

Ms Martin said the stress of being liable for the shortfalls while fighting to get the Post Office to fix the issue caused her health to dramatically deteriorate.

“It nearly killed me,” she said, adding that she suffered sleepless nights, constant kidney infections and a suspected stroke after closing the branch in early 2016.

“It devastated our lives and we need repaying and we need compensation,” she said.

Ms Martin, who is now thousands of pounds in debt, said she “still lost everything” despite never being prosecuted, which means she may not receive compensation.

Meanwhile, Susan Hazzleton, 68, said Post Office workers told her that no-one else was having computer issues like she claimed she was.

The former subpostmistress was accused of stealing £300 in 2001 after auditors checked the accounts of the Post Office branch that she had run in Chelmsford, Essex, since 1995.

Mrs Hazzleton was suspended, her shop was closed and about six weeks later she was arrested for theft, although the prosecution dropped the case 18 months later.

“It was totally unbelievable,” she said, adding that she felt the way the process was handled was “cruel”.

Mrs Hazzleton said that the shortfalls in her accounts began to “snowball” into the thousands in 2000 after she began using the Horizon system.

She said she repeatedly rang the helpline but got little assistance and ultimately paid the Post Office £4,300 to cover the missing funds before she was accused of taking the £300.

She told the inquiry tearfully: “Obviously I was very naive. I had been told I was the only one who had that problem.”

Later, Mrs Hazzleton said it was helpline workers and the area manager who had told her that nobody else was experiencing computer issues.

She said she then became aware from a magazine article that another Post Office worker had found a discrepancy of £20,000 in their accounts.

“That was a bit comforting in a way, to know that I’m not an idiot, it’s not just me going through this,” she said.

The inquiry, which is expected to run for the rest of the year, is looking into whether the Post Office knew about faults in the IT system and will also ask how staff were made to take the blame.

On Wednesday, a group of cross-party MPs called on the Government to fully compensate all victims.