Former Post Office chief executive Paula Vennells did not believe there had been miscarriages of justice and “could not have got there emotionally”, the Horizon IT inquiry has heard.

Alisdair Cameron, the business’s current chief financial officer, said in a document prepared for current chief executive Nick Read that the Post Office had an “unacceptable, self-serving” relationship with subpostmasters and the company’s “original sin” was its “self-absorbed and defensive” culture.

The document, written in November 2020, showed how Mr Cameron believed the company “should have been tackling these issues 10 years ago” but it was not “practically possible” because claimants wanted “an apology as much as they wanted money”.

He told the probe that Ms Vennells had been “clear in her conviction from the day I joined that nothing had gone wrong”.

The inquiry heard that Ms Vennells has conducted further searches and found 50 additional documents that she will hand to the inquiry on Friday before giving evidence next week.

The probe was also told Jane MacLeod, the Post Office’s top lawyer during the litigation against former subpostmaster and campaigner Alan Bates, “won’t co-operate” with the inquiry after previously being listed to give evidence next month.

The serious claimants believed there had been a miscarriage of justice and required recognition and an apology as much as they wanted money

Counsel to the inquiry Jason Beer KC said on Friday: “We’re not going to hear from her, she lives abroad and won’t co-operate”.

In Mr Cameron’s document, titled “what went wrong”, the senior executive wrote: “We should have been tackling these issues 10 years ago.

“However, I do not believe that an earlier settlement was practically possible because the serious claimants believed there had been a miscarriage of justice and required recognition and an apology as much as they wanted money.

“Paula did not believe there had been a miscarriage and could not have got there emotionally.”

Asked why he thought Ms Vennells believed there had been no miscarriages of justice, Mr Cameron said: “Everything she said at the time.

“She seemed clear in her conviction from the day I joined that nothing had gone wrong and it was very clearly stated in my very first board meeting.

“She never, in my observation, deviated from that or seemed to particularly doubt that.”

Mr Beer asked: “So she was unwavering in her conviction that there had been no miscarriages of justice?”

Mr Cameron replied: “As far as I was concerned, yes.”

He said he concluded that the Post Office had a “victim mentality” and its defence of the faulty accounting software was a “waste of public money”.

Our culture, self-absorbed and defensive, stopped us from dealing with postmasters in a straightforward and acceptable way

The document listed four criticisms the Post Office faced, which included an “unacceptable” relationship with subpostmasters “based on an imbalance of power and information and a skewed contract”.

Mr Cameron also noted that the business was criticised for being “over-reliant on Horizon when we knew its weaknesses” and that the original prosecutions of subpostmasters were a “deliberate miscarriage of justice”.

The final criticism was that the company should have “apologised and moved on years ago” and that defending itself had led to a “waste of public money and a postponement of justice”.

Asked by Mr Beer on Friday whether the criticisms had now been “established”, Mr Cameron said: “Yes, I think so.”

In the 2020 document, which was shown to the inquiry, Mr Cameron wrote: “At the heart of everything, the original sin of Post Office – and this may go back a very long time – is that: our culture, self-absorbed and defensive, stopped us from dealing with postmasters in a straightforward and acceptable way.”

Asked where the “self-absorbed and defensive” culture came from, Mr Cameron said: “I think, with all of this, it had probably been there for quite a long time.

“But I had seen it, and tried to argue with it in places – around the response to (forensic accountants) Second Sight, around some of the media responses – and I did believe and do believe that organisations should embrace challenge and criticism and have dialogues with people.”

He told the inquiry the culture remained the same until early 2020.

The Post Office has come under fire after ITV drama Mr Bates Vs The Post Office, which put the Horizon IT scandal under the spotlight.

More than 700 subpostmasters were prosecuted by the Post Office and handed criminal convictions between 1999 and 2015 as Fujitsu’s faulty Horizon system made it appear as though money was missing at their branches.

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