A Post Office investigator has denied claims he and others “behaved like Mafia gangsters” who were looking to collect “bounty with the threats and lies” from subpostmasters.

Stephen Bradshaw, who has been employed at the Post Office since 1978, submitted a witness statement to the Horizon IT inquiry in which he said: “I refute the allegation that I am a liar.”

He told the inquiry he was not “technically minded” and was not equipped to know whether there were bugs or errors in the Horizon system.

The witness began giving evidence on Thursday after being involved in the criminal investigation of nine subpostmasters, including Lisa Brennan, a former counter clerk at a post office in Huyton, near Liverpool, who was falsely accused of stealing £3,000 in 2003.

Mr Bradshaw has also been accused by fellow Merseyside subpostmistress Rita Threlfall of asking her for the colour of her eyes and what jewellery she wore before saying: “Good, so we’ve got a description of you for when they come”, during her interview under caution in August 2010.

Another subpostmistress, Jacqueline McDonald, claimed she was “bullied” by Mr Bradshaw during an investigation into a shortfall of more than £94,000.

In her interview with Mr Bradshaw, which was read to the inquiry, Ms McDonald was accused by the investigator of telling him a “pack of lies”.

The exchange between Ms McDonald and Mr Bradshaw, read by counsel to the inquiry Julian Blake, included the investigator saying: “Would you like to tell me what happened to the money?”

I had no reason to suspect at the time that there was anything wrong with the Horizon system because we’d not been told

Ms McDonald replied: “I don’t know where the money is I’ve told you.”

Mr Bradshaw continued: “You have told me a pack of lies.”

Ms McDonald said: “No I haven’t told you a pack of lies because I haven’t stolen a penny.”

Mr Blake said the witness’s words sounded “somewhat like language you might see in a 1970s television detective show”.

Responding to Ms McDonald’s allegations of his aggressive behaviour in his witness statement, Mr Bradshaw said: “I refute the allegation that I am a liar.

“I also refute the claim that Jacqueline McDonald was bullied, from the moment we arrived, the auditor was already on site, conversations were initially (held) with Mr McDonald, the reason for our attendance was explained, Mr and Mrs McDonald were kept updated as the day progressed.”

The investigator added: “Ms Jacqueline McDonald is also incorrect in stating Post Office investigators behaved like Mafia gangsters looking to collect their bounty with the threats and lies.”

Mr Blake showed Mr Bradshaw his “self-appraisal” of Ms McDonald’s case, in which the investigator said: “The offender pleaded guilty to false accounting but would not accept theft.

“I challenged the recommendations of the barrister and persuaded him that a trial would be necessary, as the reason given by the defendant, Horizon integrity, would have a wider impact on the business if a trial did not go ahead.”

Mr Blake then asked the witness: “It seems, certainly from your own feedback, from your own appraisal, that you saw it as in some way career-boosting to press on with Ms McDonald’s case because of problems with the Horizon system having a wider impact on the business, do you not accept that?”

Mr Bradshaw responded: “The issue would been discussed with the prosecution barrister – as you’re well aware, when you’re filling in one-to-ones, there’s always a flamboyant way of putting the words across.”

Throughout his witness statement, Mr Bradshaw said his investigations had been conducted in a “professional” manner.

“The investigations were done at the time, no problems were indicated by anybody that there was issues with the Horizon system

At the beginning of his evidence, Mr Blake first asked the witness: “Do you think that you have given enough thought over the past 20 years as to whether you may have been involved in what has been described as one of the largest miscarriages of justice in British history?”

Mr Bradshaw replied: “It would appear that through not being given any knowledge from top downwards that if any bugs, errors or defects were there it’s not been cascaded down from Fujitsu, the Post Office board down to our level as the investigations manager.

“I had no reason to suspect at the time that there was anything wrong with the Horizon system because we’d not been told.

“The investigations were done correctly.

“The investigations were done at the time, no problems were indicated by anybody that there was issues with the Horizon system.”

Mr Bradshaw told the inquiry that a statement signed by him declaring the Post Office’s “absolute confidence” in the Horizon IT system was written by lawyers from the law firm Cartwright King.

The statement signed by the investigator in November 2012 said: “The Post Office continues to have absolute confidence in the robustness and integrity of its Horizon system.”

Asked if it was appropriate for him to declare “confidence” in the IT system in the 2012 statement, he said: “I was given that statement by Cartwright King and told to put that statement through.

“In hindsight…there probably should have been another line stating, ‘These are not my words’.”

Mr Bradshaw was asked if, following the case of a subpostmaster named Khayyam Ishaq in 2013, having had “all those years of complaints about Horizon”, if he was not “at all concerned about the state of the Horizon system”.

The investigator, who was called as a witness in Mr Ishaq’s trial, said: “I gave my evidence, I was cross-examined by the defence and nothing untoward came from it.”

Mr Blake continued: “There was something untoward, there was a prosecution, a conviction …”

Mr Bradshaw interjected: “At the time of the case, when I gave my evidence, there was nothing untoward that had come back to me in 2013 from the defence when cross-examined.”

The statutory inquiry, which began in 2021 and is chaired by retired judge Sir Wyn Williams, has previously looked at the human impact of the scandal, the Horizon system roll-out and the operating of the system, and is now probing the action taken against subpostmasters.

The probe was established to ensure there is a “public summary of the failings which occurred with the Horizon IT system at the Post Office” and subsequently led to the wrongful convictions of subpostmasters.