Former Post Office boss Paula Vennells has broken down in tears twice mid-evidence as she made an emotional appearance at the Horizon IT inquiry.

She stopped mid-answer and reached for a tissue as she was grilled about why she had told MPs that the Post Office had been successful in every case against subpostmasters.

The 65-year-old ordained priest also became visibly upset as the inquiry looked into the Post Office’s response to the suicide of subpostmaster Martin Griffiths in 2013.

As she gave evidence on Wednesday, Ms Vennells admitted she “made mistakes” but denied there was a conspiracy to cover up the scandal.

She apologised for a comment she made to MPs in June 2012, when she said subpostmasters had been “tempted to put their hands in the till” – adding that it was an “assumption” she made.

The former chief executive said there was no “motivation” to put the needs of the Post Office over the suffering of subpostmasters but added: “There will be many examples of where that is clearly the case because the Post Office got this very wrong.”

In her first of two witness statements to the inquiry, which is 775 pages long, Ms Vennells said Fujitsu Europe’s then-chief executive described the core of Horizon like “Fort Knox” or an “aircraft flight recorder” when discussing remote access.

Ms Vennells and Duncan Tait concurred it was “implausible” that Post Office branch accounts could be altered remotely.

She said she did not know the extent of the Post Office’s criminal investigations and private prosecutions until 2012.

Ms Vennells said: “The only acceptable answer (to what is being asked) is that I should have known and I should have asked more questions, and I and others who also did not know should have dug much more deeply into this.”

The former chief executive said she “regrets” using the word “noise” in association with complaints launched by subpostmasters.

Asked if it reflected the “workings of the minds” of those at the top of the business, Ms Vennells said: “I think it reflects a wrong understanding yes that people believed that Horizon worked and this is me deploying a word that was unwise.

“I did not in any way mean that I personally did not take seriously issues when they got to me.”

She agreed that it was a “frequent refrain” of the Post Office in 2014 that there were no systemic errors in Horizon – and described it as “completely unfair to use in the business”.

Ms Vennells told the inquiry an email she sent to colleagues which suggested the company’s priority was to protect subpostmasters for whom the Horizon system was working “reads badly today”.

Ms Vennells began her evidence by apologising for “all that subpostmasters and families have suffered”.

Asked if she was the “unluckiest CEO in the United Kingdom”, she said she had been “too trusting”.

After detailing a number of cases in which the Post Office had not been successful after subpostmasters blamed Horizon, counsel to the inquiry Jason Beer KC asked: “Why were you telling these parliamentarians that every prosecution involving the Horizon system had been successful and had found in favour of the Post Office?”

After a short pause in which she appeared to compose herself, Ms Vennells said: “I fully accept now that the Post Office…”

She broke off her answer to grab a tissue and held her head in her hands for a brief moment before recomposing herself.

Ms Vennells continued: “The Post Office knew that and I completely accepted.

“Personally I didn’t know that and I’m incredibly sorry that it happened to those people and to so many others.”

Of her comment that subpostmasters were being led into temptation, Ms Vennells said: “That’s a more difficult one to talk about.

I am sorry first of all because this reads badly today

“The first thing I would say on that is to apologise, because I’m very aware that that was not the case and it was an assumption I made.”

Ms Vennells explained the assumption was based on “examples of cases” and what she had been told.

She also appeared to become emotional as Mr Beer asked her about Mr Griffiths.

An email chain between former Post Office general counsel Susan Crichton and Ms Vennells was shown to the inquiry, in which Ms Vennells said “if it is an attempted suicide, as we sadly know, there are usually several contributory factors”.

Asked why she was raising contributory factors, she said she was “very sorry”, adding: “Every email you will see from me about Mr Griffiths, I start with him and how he was and how his family are.

“The Post Office took far too long to deal with it.”

She was also shown an email she sent to former general counsel and company secretary Jane MacLeod, ex-communications director Mark Davies, and current chief financial officer Alisdair Cameron.

The email read: “Our priority is to protect the business and the thousands who operated under the same rules and didn’t get into difficulties.”

She told the inquiry on Wednesday: “I am sorry first of all because this reads badly today.

“That wasn’t how I intended it to be read.

“I had been told, and the inquiry has heard other people say the same, that nothing had been found and so my understanding at this time was that the way the business was operating was an acceptable way, and what I was trying to say here is that we needed to make sure that the business as it was operating remained a priority for us.”

Asked about what Mr Cameron told the inquiry previously – that Ms Vennells did not believe there had been any miscarriages of justice during her tenure – she said: “I think that’s right.”

Mr Beer also asked if she believed there was a “conspiracy at the Post Office… to deny you information and to deny you documents and to falsely give you reassurance”.

Ms Vennells replied: “No, I don’t believe that was the case.”

She went on: “I have been disappointed, particularly more recently, listening to evidence of the inquiry where I think I remember people knew more than perhaps either they remembered at the time or I knew of at the time.

“I have no sense that there was any conspiracy at all. My deep sorrow in this is that I think that individuals, myself included, made mistakes, didn’t see things, didn’t hear things.

“I may be wrong but that wasn’t the impression that I had at the time. I have more questions now but a conspiracy feels too far-fetched.”

Hundreds of subpostmasters were prosecuted by the business between 1999 and 2015 after Horizon, owned by Japanese company Fujitsu, made it appear as though money was missing at their branches.

The Metropolitan Police previously said they are looking at “potential fraud offences” arising out of the prosecution of subpostmasters, such as “monies recovered as a result of prosecutions or civil actions”.

Two Fujitsu experts, who were witnesses in the trials, are being investigated for perjury and perverting the course of justice, but nobody has been arrested since the inquiry was launched in January 2020.

There are unlikely to be any criminal charges until inquiry chairman Sir Wyn Williams completes his final report, which is expected to be published next year.

Hundreds of subpostmasters are still awaiting compensation despite the Government announcing that those who have had convictions quashed are eligible for £600,000 payouts.