Some more context on the penultimate line of our last post now.

Inquiry counsel Jason Beer KC returns to the Gareth Jenkins report, which highlighted issues with the Horizon system.

Beer notes how the bottom of the page it is indicated that Singh himself printed the report.

"You know that you got this document, its contents and you know that you printed it," he says. Singh says no.

Beer says this is "evidence of his own guilty conscience".

"My evidence on oath is that I don't remember receiving it or printing it," Singh answers.

Emma Simpson
Business correspondent, reporting from the inquiry

Jarnail Singh has been sticking to the line that he didn’t know about the existence of bugs until couple of days before the Second Sight interim report in 2013.

But Jason Beer has now reminded him that he was forwarded on a report about one of the bugs on the eve of the Seema Misra trial three years earlier. And there's the evidence that he printed it out, and it was saved on his drive.

But Singh is insisting that he doesn’t recall receiving it, reading it or printing it.

"I don’t feel guilty...that’s my evidence on oath," he says.

Image source, Post Office Horizon IT Inquiry

A report by Fujitsu engineer Gareth Jenkins is shown to the inquiry - it was written in 2010 - a few days prior to the trial beginning.

The Jenkins report outlines discrepancies and mismatches in the system, Beer says.

Singh maintains: "I don't know anything about this."

Beer then pulls up an email from October 2010, showing Singh was sent the information about the same report.

As someone who was prosecuting sub-postmasters at the time, this email ought to "ring alarm bells", Beer puts to him, because it shows money disappearing at branch level.

"Yes," but Singh says, but adds: "I don't recall reading this email".

Beer now suggests that Singh had known about the bugs in the Horizon IT system all along, which Singh again denies.

"You were covering it up in 2013 and 2015...you were covering up your own guilty knowledge," Beer says. "No," the former Post Office lawyer hits back.

Beer now accuses Singh of knowing about the "mismatch" bug, as it was known internally. This was causing discrepancies between the accounts postmasters saw and those on the Post Office main servers.

The inquiry counsel says that Singh had his time to own up in 2014 and 2015.

"Everything you've said is not true," Singh insists.

Beer then accuses him of trying to cover up the Horizon issues from 2013 onwards.

"This is not true," Singh says and adds: "I would have never cover up anything of that magnitude."

Beer turns to the case of former sub-postmistress Seema Misra. She was eight weeks pregnant with her second child when she was wrongly convicted and sentenced to 15 months in prison.

Beer notes that the Horizon bugs were not disclosed to the defence or the court in the course of or before her trial.

"Were you aware of this?" Beer asks. Singh says he can't recall.

It's getting a bit heated, as Beer says: "This was one of your cases that you prosecuted - you must know there was no disclosure," Beer insists.

Singh maintains his consistent line: "I wasn't aware of that."

Tom Espiner
Business reporter

Jarnail Singh was warned about self-incrimination after being sworn in at the Post Office Horizon enquiry. He had promised to tell the truth while wearing a white turban, which for Sikhs indicates someone who has led an exemplary life.

The opening exchange between inquiry lead counsel Jason Beer and Singh was spiky.

After apologising for the "state" of his voice due to having flu, Beer launched into a series of searching questions: was Mr Singh involved from July 2013 onwards in a cover-up of his own prior knowledge, and the Post Office's prior knowledge, of the existence of bugs, errors and defects in Horizon? "No sir", Singh responded.

Specifically, did Singh have knowledge of bugs in Horizon before July 2013? "Not to my knowledge, no".

"But you sought to cover up that knowledge because you knew that it ought to have been disclosed in criminal proceedings, but was not disclosed?" Beer asked. "No sir".

Did anyone else at Post Office know but seek to cover that up? "Not to my knowledge, sir?".

Has Singh been pretending that he didn't know of any bugs before July 2013? He denies it. The emphasis on the July 2013 date is because that was when Second Sight published its report into Horizon that identified certain bugs.

Beer is struggling to get a straight answer from Singh, as he continues to push him on what he knew about the two Horizon defects raised by Second Sight.

He returns to the same email mentioned in our last post, in which Singh suggested it would have been "highly embarrassing" for the Post Office if it transpired that Fujitsu had informed people at the company about problems with Horizon, but that the information never reached the security team.

Singh says he can't remember exactly why he would have written that.

"Think about it hard now," Beer says. "Wouldn't it have been highly embarrassing because the security team were bound up in the prosecutions?"

Singh says he's not sure what he's being asked.

Beer suggests it would be even more embarrassing if it emerged if Fujitsu had passed on information about the two bugs to the in-house legal team.

Singh maintains: "I can't answer that".

Image source, Post Office Horizon IT Inquiry

Jason Beer, inquiry counsel, pulls up an email sent by Singh in January 2015 - addressed to several top Post Office execs.

In it, he reflects on a request from the BBC for an interview about the issues in Horizon system.

Beer reads out a section of the email relating to Gareth Jenkins, a Fujitsu employee who helped wrongly jail pregnant postmistress Seema Misra.

In the email, Singh writes that Jenkins had been making statements for use in criminal proceedings about bugs not being found in Horizon, despite the Second Sight findings.

The Post Office is entering "dangerous territory", he said at the time.

Beer asks Singh if he was suggesting that he was again unaware of the bugs.

Singh says his involvement was very limited, adding that his involvement in Misra case was also "very, very limited".

Beer now asks if the Post Office top brass were unaware of the bugs until the Second Sight report was published.

Singh again says: "The only issues I was aware of were the case of Seema Misra."

Image source, Post Office Horizon IT Inquiry

Beer continues to push the ex-Post Office lawyer on what specific Horizon bugs he was aware of and when.

He raises two defects raised in the Second Sight report. These affected 76 branches and created both positive and negative discrepancies, he says.

Beer asks Singh if it is correct that he "unaware" of these two bugs, despite them having been laid out in the report.

"I don't remember at all," Singh says. "It wasn't something I was involved in."

Inquiry counsel Beer turns his focus on the Second Sight interim report, which found flaws in the Horizon system and played a key role in exposing the scandal.

He highlights known defects which affected dozens of Post Office branches and created discrepancies in sub-postmasters' accounts.

In his witness statement, Singh says he did not recall seeing the interim report. He also says he was unaware of the bugs and how long they had existed in the system for.

Speaking to the inquiry, Singh insists that the only bugs that he was aware of related to the case of Seema Misra.

"Was there a cover up?" is the opening question of inquiry counsel to Singh, asking if he attempted to conceal any prior knowledge of defects and bugs in the faulty Horizon IT system before July 2013.

Singh says: "No, not to my knowledge."

Beer pushes him again, asking if he pretended that he first knew of the bugs when he saw the Second Sight report in the same month.

Singh again replies: "Not to my knowledge, no."

Image source, Post Office Horizon IT Inquiry

Janail Singh takes his seat in front of the inquiry and his evidence session gets underway.

He's being "re-sworn" in today, having previously given evidence to the inquiry.

Watching on are Seema Misra and her husband. Singh was part of the legal team involved in her prosecution and wrongful imprisonment in 2010. She was pregnant at the time.

You can watch along by pressing the play button at the top of this page.

Who knew what about Horizon and when?published at 09:44 British Summer Time 3 May

09:44 BST 3 May

Emma Simpson
Reporting from the inquiry

A bit more background before we get going.

There was a bug that came to light a month or so before Seema Misra’s trial. It was written by Fujitsu Horizon engineer Gareth Jenkins. In it, he says if we “amend the data” this will need to be “carefully communicated” to branches to “avoid questions about the system integrity”.

There was also a meeting about it, which he attended, and we’ve seen a record of the discussion. It noted the “potential impact upon ongoing legal cases where branches are disputing the integrity of Horizon data”.

There’s evidence all this material was forwarded in an email to Jarnail Singh on the Friday before Misra’s trial was set to begin on the following Monday.

He was supposed to disclose any relevant information to her defence team, but this was never passed on. And Jenkins gave evidence as the star expert witness for the Post Office. He didn’t disclose the material, either.

Emma Simpson
Reporting from the inquiry

Jarnail Singh is back for a second time answering questions today. He was a senior lawyer at the Post Office and was made head of criminal law in 2012 after the split with Royal Mail.

In Phase 4 he was grilled about his role in a host of prosecutions. His name's been popping up a fair bit in this phase of the inquiry as well.

He sent the "Horizon-bashing bandwagon" email to a number of colleagues celebrating the conviction of Seema Misra in 2010. It was hard for barristers to get a straight answer out of Singh the first time round with his often garbled responses and "don't recalls".

Today, he'll be quizzed on his knowledge about the broader corporate decisions being made at the time, but he'll likely face more questions about the Misra case, which the Post Office badly wanted to win to protect the integrity of the Horizon system.

Today we will hear from Jarnail Singh, the Post Office’s former head of criminal law. He was the senior lawyer involved in a number of prosecutions - including that of postmistress Seema Misra, who was sent to jail in 2010 and later cleared of wrongdoing.

Singh appeared at the inquiry last year and admitted that an email he sent following the prosecution was at odds with his professional duties.

In this letter, he wrote of the Post Office’s legal team “destroying” all of Misra’s arguments and said that he hoped the result would “set a marker to dissuade other defendants from jumping on the Horizon-bashing bandwagon”.

He denied at the inquiry that he had seen Misra’s defence as an attack on Horizon, nor that he viewed her case as a deterrent for further criticisms of the system.

Image source, EPA

Hello and welcome to our latest coverage of the Post Office inquiry, which is investigating what led to the prosecution of hundreds of sub-postmasters over data from the faulty Horizon IT system.

Today, we’ll be hearing from Jarnail Singh, who was part of the Post Office in-house legal team and was the senior lawyer involved in the prosecution of sub-postmasters including Seema Misra, who was wrongly jailed in 2010 while she was pregnant.

Singh’s name has come up several times in the inquiry in relation to what was known about failings in the Horizon IT system and when it was known.

We are expecting to hear more from him about the role Post Office lawyers played in the prosecution of sub-postmasters, especially as it relates to Horizon.

Stay with us as we bring you all the latest updates and analysis from the inquiry.