Rishi Sunak has been urged not to forget the “hidden victims” of the post office scandal after an Edinburgh supermarket worker spoke of the toll taken on her mental health as a result of the faulty Horizon software.

Mary - not her real name - told The Herald on Sunday of how she was bullied by colleagues and drummed out of her job at a post office franchise in an Edinburgh supermarket because of a computer glitch.

Details of her plight were raised with Rishi Sunak last week by MP Joanna Cherry, who said her constituent was due an apology and compensation.

The Prime Minister has promised to look into Mary’s situation.

READ MORE: Scots Post Office scandal victims still in dark over justice

Mary worked at the post office franchise in the supermarket between 2007 and 2013.

She said there were frequently problems with the software, often showing shortfalls in the takings of her and her colleagues.

“It was never huge amounts, but it was never even an exact amount. It was never exactly £10, £15 or whatever. It would be automated. And it was always put down to human error. We’d be told we'd miss-keyed something or we'd given out too much change.”

“With hindsight, it should have been a red flag that it was always a shortage,” she added. “There was never any overages.

“If it was human error, you would imagine that at some point, you would be over.”

Mary was working on a bank holiday in 2011, with just one other colleague.

Because most other branches were closed, business was brisk, with customers coming in all day and little chance to take a break.

“The queue was so huge. It was ridiculously busy. And you'd be on the go constantly all day. And so there was never a chance to do anything other than be on the counter and serving.”

“We did our thing. And we close the post office and we started balancing our stock and my stock was a bit shy of £400 short. I kind of looked at this in sheer horror and thought what the hell have I done that's made that happen?”

Mary said she went through every transaction looking to see where she had made a mistake. Her colleague looked through it too and could see nothing unusual.

And then the amount showing short on the computer just jumped.

“It went from short of £400 to £700 and I was like, what?”

“I spent the night worrying myself stupid, because this had never happened happened to me before," she added.

READ MORE: Horizon: Scottish narrative simply does not compute

When she went back into work she was told she was facing a disciplinary hearing because of the shortfall.

Despite the suspicion, Mary said she was not suspended nor was her work subject to any extra checks.

“With hindsight, if they actually thought I'd stolen money, surely they should have done one of those things, but they didn't?”

The hearing lasted all day and when she was asked to explain the shortfall, she said she could not.

“The whole disciplinary consisted of trying to trip me up, trying to find ways to say that I had stolen money. By the time I got to the end of it, I was worn out.

“I was stressed to the eyeballs because I really felt like they were just not interested in anything I had to say.”

“They had decided I'd done something wrong.

"Basically, I was told that they couldn't find any evidence that I hadn't stolen money. I said, ‘You may not be able to find any evidence that I didn't steal the money by I'm damn sure you can't find anything whatsoever to say that I have stolen money because I haven't touched one single penny’.”

Mary was not sacked, but the way she was treated by management and colleagues put her under immense pressure.

“The atmosphere in the post office towards me was completely different. And it never felt friendly again, it always felt like there was a cloud hanging over me, some sort of suspicion.”

She had little choice but to leave. The toll the experience took on her lasted years, leaving her feeling guilty and incapable, denting her confidence when it came to trying to find new work.

“The stress just got too much for me. I just couldn't continue to function in that role. And it was a long time after that, before I really felt able to sort of look for another job, working wth money or customers or anything like that. It was a few years before I felt really able to sort of look for a job like that.”

The Herald:

It was Mary’s husband who first watched Mr Bates Vs the Post Office, telling his wife that she needed to tune in.

“I binge-watched the whole thing in one go,” she said.

“Because we weren't Post Office employees it never ever occurred to me that any of it was to do with the Post Office.

“I had spent years blaming myself and thinking well it must have been me because nobody else had that problem in our office. But when you look at it with hindsight and having watched the drama and everything, it's like, well, I can't possibly be the only person who's been in this position.“

Mary was not looking for compensation or an apology when she approached Joanna Cherry. She wanted to lend her support to the subpostmasters and postmistresses and tell her story as a way to back up some of the claims.

But the MP made clear that after all these years Mary is due some sort of recognition.

READ MORE: SNP drawing up own laws to exonerate Horizon victims after UK warning

Ms Cherry raised Mary’s case with Rishi Sunak during Wednesday’s Prime Minster’s Questions.

She told the Conservative leader that there were undoubtedly others in the same position as her constituent.

Yet, she pointed out, “there is no provision for compensating people who worked in franchise post offices, as she did.”

She urged the Prime Minister to include those victims in the Horizon scandal compensation scheme.

The Herald:

Mr Sunak said he was sorry to hear about Mary’s case.

He told the Commons: “As I have said, it was an awful miscarriage of justice and everyone affected deserves not only justice, but compensation and answers. I will make sure we look into the precise details of her constituent’s case—surely there will be others like that—and will make sure that the Minister gets back to her with all due haste.”

Ms Cherry told The Herald on Sunday: “People who were employed in franchise Post Offices and suffered disciplinary action or were sacked as a result of Horizon losses remain hidden victims of this scandal.

“The Government must make sure that everyone whose life was impacted by the faulty Horizon system receives the apology and the compensation they deserve.”

Ms Cherry said anyone in a similar situation should contact their own MP and "ensure their case is sent to the minister in charge Kevin Hollinrake.”

Mary said she was only starting to get her head round the fact that she is a victim of Horizon.

“There are going to be other people in my position who nobody ever knew about.”