The head of Fujitsu Europe has admitted he “doesn’t know” whether the Post Office Horizon IT system at the center of the wrongful convictions of hundreds of sub-postmasters is reliable.

Paul Patterson told the inquiry into the scandal that “there were errors and flaws” in the accounting system and it was clear “that there was a level of insecurity” at Horizon.

He agreed that this would be a problem for sub-postmasters currently using Horizon.

In his second appearance before the inquiry, Mr Patterson also admitted he did not know whether Fujitsu had made an independent report into the software system.

Although he added that he would welcome a third-party investigation.

Between 1999 and 2015, hundreds of sub-managers and station mistresses were wrongfully prosecuted after Horizon made it appear that money was missing from their branches.

The Fujitsu Horizon contract is up for renewal early next year and could be extended for another five years.

Patterson said he is “very concerned” about what might happen if the contract is extended because of how unsafe Horizon is.

“In my experience … if you don’t keep (IT systems) up to date, I can’t determine what will or won’t happen, which is part of my expansion nervousness,” he said.

Monday marked the start of the final week of evidence at the inquest, more than two-and-a-half years since it began hearing evidence in public.

Mr Patterson said Fujitsu had pledged to pay compensation to victims of the scandal, calling it “a moral obligation”, but said the firm was waiting until the end of the investigation before doing so.

In a heated exchange with Sam Stein KC, who represented some of the victims of the scandal, Mr Patterson was pushed to explain why this was.

“You already accept that there is a need for Fujitsu to put its money where its mouth is,” Mr. Stein said.

Mr Patterson said the company wanted to hear all the evidence from the inquiry before proceeding. “These are complex issues and we need to understand all the components,” he said.

Earlier in the day, Conservative Party leader Kemi Badenoch gave evidence – as former business secretary, the government-owned post office was her remit.

She said the airing of the TV drama in the Post Office scandal “brought the urgency” to speed up compensation payments for sub-postmasters.

The government needed to be “seen to be doing the right thing”, Badenoch said.

She accepted at the inquest into the scandal that it was “extremely disappointing” that it took the ITV drama to escalate the issue.

But she said her discussion with the Treasury over the time it took to issue compensation last August was not just a case of “posting”.

Badenoch said the four-part ITV drama Mr Bates vs The Post Office, which aired in January, had raised awareness of the issue, turning compensation from “a perception of value for money to a perception issue public”.

She insisted the previous government was working on the issue, but admitted it was “too slow” and criticized the whole “machinery of government” for slowing down compensation.

The inquiry heard how Badenoch told the Treasury he wanted to give “fixed offers” of £100,000 to all sub-postmasters with a claim, with the inquiry to councilor Jason Beer KC describing the mention of “ministerial direction” as a threat.

He said this could be seen as “soft power” or “posturing”.

But Badenoch denied the claim, saying: “It was a signal of the direction we wanted the department to take to be very clear.”

She said she believed speed should triumph over accuracy and admitted it might not have been value for money from the taxpayers’ point of view.

Badenoch was also polled for her the dismissal of former Post Office President Henry Staunton.

She said she didn’t know how serious the concerns about him were because of “vanilla updates” from public officials.

Her statement of evidence provided her reasons for sacking Mr Staunton, which included the former president attempting to close an investigation into his conduct, behaving in an aggressive, intimidating and disrespectful manner and having a poor understanding of the activity of the Post Office.

Mr Staunton previously defended himself after a report found he used derogatory language during a meeting about recruiting a board member. He also dismissed Badenoch’s claim that he was under an “official investigation” for “serious issues such as harassment”.

Earlier on Monday, Business Secretary Jonathan Reynolds said ownership of the Post Office could be handed to thousands of sub-postmasters across the UK.

“Nothing should be ruled out for the future of the post office,” he said, adding that the future of the organization would be decided in the first half of next year.

He said the corporate culture of the post office was “at the root of this scandal” and that some sub-postmasters had “lost all faith in the justice system” because of it.