The former Post Office chief executive Paula Vennells and other senior executives searched for “non-emotive” words to describe computer bugs found in the company’s Horizon IT system in an “absolutely Orwellian” use of language, a public inquiry has heard.

The inquiry is investigating why the Post Office hounded and prosecuted post office operators for more than a decade because of shortfalls in their branch accounts. It has since emerged that these discrepancies were due to IT problems in the Horizon computer system.

Susan Crichton, a former senior lawyer at the Post Office between 2010 and 2013, told the inquiry that an independent investigation by the forensic accountants Second Sight had identified bugs in Horizon by July 2013.

The inquiry was shown an email by Vennells, sent in July 2013 to Mark Davies, the Post Office’s then head of communications, in which Vennells said she had asked her “engineer/computer literate husband” to help find a “non-emotive word for computer bugs”.

Her email to Davies read: “My engineer/computer literate husband sent the following reply to the question: ‘What is a non-emotive word for computer bugs, glitches, defects that happen as a matter of course?’”

Her husband replied: “Exception or anomaly. You can also say conditional exception/anomaly which only manifests itself under unforeseen circumstances.”

Problems with post office branches were later referred to as “branch exceptions” rather than “bugs” in a note prepared for a meeting between the Post Office and James Arbuthnot, then a Tory MP who was campaigning for wrongly convicted operators, the inquiry heard.

Julian Blake, the counsel to the inquiry, put it to Crichton that there was “discussion within the business at the highest levels” about “changing the language around these bugs” so it was “less emotive language”. Crichton said she did not recall a discussion around language.

“Are we to understand here that words suggested by Paula Vennells’s husband have now made their way into the terminology that’s being used by the business,” Blake asked Crichton, adding it was an “absolutely Orwellian” use of language.

“That’s what it looked like,” she replied.

Crichton was also asked why she had suggested that operators with criminal convictions including Seema Misra should be excluded from Second Sight’s investigation.

Misra is one of the highest-profile victims of the Post Office scandal. She was sentenced to 15 months in prison for theft and locked up on her son’s 10th birthday while eight weeks pregnant. She was placed on suicide watch after collapsing in court. Her conviction was among those overturned by the court of appeal in 2021.

Crichton replied: “I was very concerned about the situation. I understood what had happened was very concerning and I did not want to reopen it [the Misra case] unless we had good reason to.”

She told the inquiry: “I agree it was too shortsighted maybe.”

Crichton also used her appearance before the inquiry to apologise to the post office operators and say she was “truly sorry for the suffering” caused to them and their families by the scandal.

The inquiry continues.