An ex-Post Office investigator said he “wouldn’t have done anything differently” in the probe of a subpostmaster who was wrongly convicted while pregnant, the inquiry heard.

Jon Longman insisted the initial investigation into Seema Misra was done “properly”. Pressed by inquiry lawyers, he clarified that there were things he wished he'd done differently when her case got to court. “I think I would have been more forceful in making sure that the disclosure requests were all actioned if I had that authority," he said.

The inquiry heard the Post Office was reluctant to spend £15,000 on producing five years of transaction log data in Ms Misra’s case. Ms Misra said she was “angry” as she watched Mr Longman’s evidence.

“When I saw that £15,000 figure – I couldn’t believe it. They were willing to let an innocent person go to prison to save £15,000,” she told the Telegraph. “People committed suicide as a result of this scandal – you had CEOs receiving millions of pounds, but they were worried about spending £15,000 on disclosure – it’s completely unethical.”

She also criticised Mr Longman for suggesting he wouldn’t change his actions in his initial probe of her. Describing the search he and his colleagues conducted, she added: “He was going through my house from the morning to the evidence and they were there that long because I had nothing to hide. I had a freezer and they moved that to see if there was anything behind it. Then I had a temple in a room and I asked them to remove their shoes but they didn’t, it was so horrible.”

Ms Misra, who ran a post office in West Byfleet, Surrey, was wrongfully sentenced to 15 months in jail in 2010 after being accused of stealing £74,000. The 48-year-old mother-of-two, who had to give birth wearing a tag, told the Mirror last week she still has nightmares about her time behind bars.

Mr Longman admitted the case of Ms Misra turned into a "test case". "It developed... and I didn't know this at the time, I think there were a lot of people in different departments within the Post Office watching the outcome very closely,” he added. "So it developed into a bit of a test case, I suppose you could say."

He was also asked about an ex-Post Office lawyer who celebrated Ms Misra’s prosecution as it would stop other subpostmasters “jumping on the Horizon bashing bandwagon". Senior lawyer Jarnail Singh told Mr Longman in an email that he hoped her case in 2010 would dissuade other potential defendants from blaming issues with the Horizon IT system for shortfalls in their accounts.

"I'd have to say that I don't know why that comment was put in - it wasn't necessary and I didn't respond to that email,” Mr Longman told the inquiry. “I remember it clearly and I don't see that there was a Horizon bashing bandwagon going on."

Separate from the inquiry, Post Office chief executive Nick Read was "exonerated of all misconduct allegations'' following an external report into his behaviour, the organisation has said.

In a statement, the Post Office said: "Over the last few months an independent barrister has been investigating a Speak Up complaint into various allegations, which included a number of misconduct allegations against our CEO, Nick Read. Following several interviews and examination of documents by the barrister, Nick has been exonerated of all the misconduct allegations and has the full and united backing of the board to continue to lead the business.”

Rishi Sunak met with subpostmasters caught up in the Horizon IT scandal after PMQs, where he discussed No10’s work in delivering “quick and fair justice” to all victims.