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Thousands of known errors on controversial Post Office computer system to be revealed

Known errors log concerning Horizon IT system set to be announced during second High Court trial in subpostmasters’ long-running dispute with Post Office over financial losses

Thousands of errors in the Post Office Horizon IT system and supporting services are expected be revealed during a High Court trial, in which subpostmaster claimants are blaming computer problems for unexplained financial losses.

According to Computer Weekly sources, the known errors log has been disclosed in preparation for the second trial in a group litigation order (GLO), and will reveal thousands of errors that the Post Office and Fujitsu knew about but did not inform the subpostmaster network.

Sources suggest that disclosure of the known errors log, which records errors in the Post Office Horizon retail and accounting system and supporting services used by subpostmasters, will reveal hundreds of bugs potentially capable of leading to losses. Nearly 12,000 post offices rely on the Horizon system, which was introduced in 1999/2000, to run their businesses and are held liable for any unexplained losses.

The log of known errors in the system, amassed over its 19-year service, has never been made available to subpostmasters, while the Post Office has consistently denied there are problems with the IT system. Alleged fallibilities within the system are at the centre of the GLO being heard in the High Court, where the Post Office is being sued by more than 550 subpostmasters.

Claimant subpostmasters say they experienced life-changing hardship after being punished for losses that they blame on the computer system. In 2009, Computer Weekly told the stories of seven of the postmasters affected. Some received heavy fines and had to repay thousands of pounds because of unexplained shortfalls in their accounts. Some lost their life savings and went bankrupt. Others were sent to prison, one while pregnant.

Even when the issue was first revealed in 2009, Post Office claimed there were no errors in the system. At the time, a spokesman said: “There is no evidence that points to any fault with the technology. We would always look into and investigate any issues raised by subpostmasters.”

The claimants in the trial are seeking damages that could run into many millions of pounds if the case goes their way.

Subpostmasters suspected that problems with Horizon, which was developed by ICL/Fujitsu Services, were causing accounting shortfalls, for which the Post Office held them liable.

Post Office denied allegations

The Post Office has always denied the allegations about Horizon, and said there were no problems with the system that could have caused unexplained losses for subpostmasters. Leading up to the current trial, the Post Office reaffirmed its confidence in the Horizon system in a statement to Computer Weekly that said: “We have confidence in the Horizon system, which is robust, reliable and used across 11,500 branches by postmasters, agents and their many thousands of staff to process millions of transactions successfully every day, including on behalf of the UK’s high-street banks.”

When subpostmasters sign a contract with the Post Office, they take on responsibility for all unexplained losses.

During cross-examination in the first trial in November, Post Office director Angela van den Bogerd admitted that the Horizon IT system had made mistakes which the Post Office was responsible for correcting, but said the Post Office did not necessarily have to tell its subpostmaster network about the errors. Van den Bogerd said the Post Office could have told subposmasters about the errors, but did not.

The known error log disclosure is part of March’s trial, the second of four currently planned, which will focus on the computer system and supporting processes at the centre of the case. The first trial, which took place in November last year, looked at the contractual relationship between subpostmasters and the Post Office. The judgment on that is expected later this month.

A third trial, scheduled for October 2019, will focus on individual subpostmasters’ claims and a fourth trial will probably be held in early 2020.

The revelation that the Horizon system has thousands of errors is no surprise to the IT community. Computer Weekly has written about the system’s problems in the past.

In November 2015, the Communication Workers Union (CWU) wrote to subpostmasters warning them of a problem with the system following an incident in which thousands of pounds’ worth of payments were duplicated for one subpostmaster.

If undetected, this would have appeared as losses when the accounts were completed, which would be the responsibility of the subpostmaster. In relation to this, Post Office IT support sent an email to a member of the postmasters’ branch of the CWU revealing the flaw.

In an email at the time, an Atos representative said this was not an isolated incident, noting: “This issue is caused by the user forcing log-off when the post-login checks have not fully completed. We have experienced previous instances of this issue in other branches that have been caused in the same way [forced log-off].”

Evidence of errors

In the first trial, the court heard evidence of errors caused by Horizon that had led to inaccurate accounts at some branches. The error was revealed in a Post Office internal memo from August 2010, which was revealed in court.

The memo said discrepancies showing at the Horizon counter disappeared when the branch followed certain process steps, but would still show in the back-end branch account. “This is currently impacting circa 40 branches since migration onto Horizon Online, with an overall cash value of circa £20k loss,” the memo said.

But the Post Office did not reveal the error to the subpostmaster network. “If widely known, it could cause a loss of confidence in the Horizon system by branches,” the internal memo said.

In a statement with regard to the trial, the Post Office said: “The Post Office is robustly defending its position in the court and welcomes the opportunity to do so. We take these cases extremely seriously and we have worked hard over a number of years to address the issues raised.

“We have conducted thorough investigations and sought to resolve some of the claims through mediation. Our employees and postmasters are important to us and we take our relationships with them very seriously.

“We have confidence in our network of 11,500 Post Office branches and the systems underpinning it. The Horizon computer system is operated successfully by thousands of employees, postmasters and their staff to process 47 million transactions every week.”

Glitches no surprise

One IT professional in the UK banking sector, who has worked on many complex computer systems, said it did not surprise him that there were thousands of glitches in a very large IT system such as Horizon.

“But I would be shocked if critical known bugs had not been addressed as soon as they were identified,” he said. “It is inevitable that some bugs and issues will get past design and testing, so the trick is to ensure the system is monitored closely in operation so that any problems can be identified and handled appropriately.”

The IT professional said users must be able to escalate any bugs they believe they have found and the system operator must manage these responsibly. “If users are not made aware of scenarios that can cause system glitches and the operator does not fix them, this is a recipe for disaster,” he added.

“Covering up a long list of known and unresolved bugs in a major system is unlikely to be forgiven by anyone if they materially affect critical functions, such as financial control and accounting.”

The subpostmasters’ case against the Post Office continues.

Separately, the Criminal Courts Review Commission (CCRC) is reviewing about 30 claims from subpostmasters that they were wrongfully prosecuted as a result of problems with the Post Office’s Horizon IT system, through which they file accounts.

The CCRC was due to announce its decisions on the cases under review, but will now wait until after the High Court judge’s ruling on the first trial in the GLO. It might then decide to wait until after the March trial.

Timeline of the Post Office Horizon case since Computer Weekly first reported on it in 2009

May 2009: Bankruptcy, prosecution and disrupted livelihoods – postmasters tell their story

September 2009: Postmasters form action group after accounts shortfall

November 2009: Post Office theft case deferred over IT questions

February 2011: Post Office faces legal action over alleged accounting system failures

October 2011: 85 subpostmasters seek legal support in claims against Post Office computer system

June 2012: Post Office launches external review of system at centre of legal disputes

January 2013: Post Office admits Horizon system needs more investigation

January 2013: Post Office announces amnesty for Horizon evidence

January 2013: Post Office wants to get to bottom of IT system allegations

June 2013: Investigation into Post Office accounting system to drill down on strongest cases

July 2013: Post Office Horizon system investigation reveals concerns

October 2013: End in sight for subpostmaster claims against Post Office’s Horizon accounting system

October 2013: Former Lord Justice of Appeal Hooper joins Post Office Horizon investigation

November 2013: 150 subpostmasters file claims over ‘faulty’ Horizon accounting system

September 2014: Fresh questions raised over Post Office IT system’s role in fraud cases

December 2014: MPs blast Post Office over IT system investigation and remove backing

December 2014: Why MPs lost faith in the Post Office’s IT investigation, but vowed to fight on

December 2014: MPs to debate subpostmaster IT injustice claims

December 2014: MP accuses Post Office of acting “duplicitously” in IT investigation

January 2015: MPs force inquiry into Post Office subpostmaster mediation scheme

January 2015: Post Office faces grilling by MPs over Horizon accounting system

February 2015: Post Office CIO will talk to any subpostmaster about IT problems, promises CEO

March 2015: Post Office ends working group for IT system investigation day before potentially damaging report

March 2015: MPs seek reassurance over Post Office mediation scheme

March 2015: Retiring MP aims to uncover truth of alleged Post Office computer system problems

April 2015: Post Office failed to investigate account shortfalls before legal action, report claims

April 2015: Criminal Courts Review Commission set to review subpostmasters’ claims of wrongful prosecution

May 2015: IT system related to subpostmaster prosecutions under review by CCRC

June 2015: Post Office looking to replace controversial Horizon system with IBM, says MP

July 2015: Campaigners call for independent inquiry into Post Office Horizon IT system dispute

October 2015: James Arbuthnot takes Post Office IT fight to House of Lords

November 2015: The union that represents Post Office subpostmasters has warned of a problem with the Horizon accounting system

November 2015: An email from Post Office IT support reveals a problem with the Horizon system and supporting processes that could lead to accounting errors

November 2015: Group litigation against Post Office being prepared in Horizon dispute

February 2016: Post Office faces group litigation over Horizon IT as subpostmasters fund class action

June 2016: Post Office chairman Tim Parker says there would be “considerable risk” associated with changing its Horizon computer system

November 2016: The legal team hired by a group of subpostmasters will take their case to the next stage

January 2017: The group action against the Post Office that alleges subpostmasters have been wrongly punished for accounting errors gets a green light from the High Court of Justice

March 2017: 1,000 subpostmasters apply to join IT-related group litigation against Post Office

April 2017: Investigation into claims of miscarriages of justice in relation to a Post Office accounting system has appointed a forensic accountant firm

May 2017: Hundreds of subpostmasters have applied to join IT-related legal action since March

July 2017: Post Office defence in computer system legal case due this week

August 2017: Campaigners submit initial evidence in group litigation against Post Office over controversial Horizon IT system

October 2017: Subpostmasters’ group action against the Post Office reaches an important milestone

November 2017: An end is in sight for subpostmasters’ campaign against alleged wrongful prosecution, which they blame on a faulty computer system

November 2017: The high court judge managing the subpostmasters versus Post Office legal case over an allegedly faulty computer system tells legal teams to cooperate

January 2018: Forensic investigation into Post Office IT system at centre of legal case nears completion

April 2018: Criminal Cases Review Commission forensic examination of the IT system at the centre of a legal case against the Post Office has raised further questions

May 2018: Post Office branches unable to connect to Horizon computer system for several hours after morning opening time

October 2018: After over a decade of controversy, next week marks the beginning of a court battle between subpostmasters and the Post Office

November 2018Case against Post Office in relation to allegedly faulty computer system begins in High Court

November 2018: High Court case in which subpostmasters are suing the Post Office has revealed a known problem with a computer system at the core of the dispute

November 2018A High Court trial, where subpostmasters are suing the Post Office for damages caused by an allegedly faulty IT system, ends second week

November 2018: Post Office director admits to Horizon errors and not sharing details with subpostmaster network

November 2018: The High Court trial in which subpostmasters are suing the Post Office has reached an important stage

December 2018: CCRC may hold off subpostmaster decision until after Post Office Horizon trial

December 2018: Court case where subpostmasters are suing the Post Office set to span at least four trials and extend into 2020

January 2019: Subpostmasters’ campaign group attacks Post Office CEO Paula Vennells’ New Year honour amid ongoing court case

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