WTF?! A Fujitsu executive has admitted that bugs in its Horizon accounting software that mistakenly led to almost 1,000 UK Post Office workers being convicted for theft or fraud were known about by both businesses from the start. The scandal led to some workers being sent to prison and is linked to at least four suicides.

In 1999, Fujitsu subsidiary International Computers Limited installed the Horizon software system in UK post offices. Up until 2015, it was used to prosecute and convict more than 900 sub-postmasters and postmistresses for theft and false accounting after money appeared to be missing from their branches. The bug-riddled Horizon was used as evidence for the prosecutions.

Some of those wrongly accused were sent to prison. Many of the victims faced financial ruin and saw their lives and relationships fall apart after being forced to pay back money that had never been stolen in the first place and the massive legal fees. There have also been four known suicides among those wrongfully accused.

More than 20 years later, only 93 convictions have been overturned while thousands are still waiting for compensation settlements, writes the BBC.

As part of a public inquiry into Fujitsu's reluctance to make Horizon's defects known to the Post Office, Paul Patterson, co-CEO of Fujitsu's European division, said "All the bugs and errors have been known at one level or not, for many, many years. Right from the very start of deployment of the system, there were bugs and errors and defects, which were well-known to all parties."

Patterson said the fact that the courts were not told of the 29 Horizon bugs despite them being identified as early as 1999 was "shameful and appalling."

When the Horizon bugs were acknowledged, witness statements from Fujitsu staff were edited by the Post Office's lawyers to make it appear as if the system was working without any issues as they continued with their prosecutions against innocent workers. Patterson added that in some witness statements, Fujitsu did not include details of Horizon's many problems, and that the "vast majority" of bugs, errors and defects were shared with the Post Office.

"I am surprised that that detail was not included in the witness statements given by Fujitsu staff to the Post Office and I have seen some evidence of editing witness statements by others," Patterson said. When asked if he considered this behavior to be shameful on the part of companies, the executive said "That would be one word I would use."

Fujitsu is under pressure to contribute to the £1 billion ($1.2 billion) UK government ministers have allocated to compensate victims. Patterson said the Japanese company is truly sorry for its part in the "appalling miscarriage of justice," and that it has a "moral obligation" to contribute to the compensation of those affected.

The Post Office has been asked by the government to look at its previous accounting system, Capture, which also resulted in false convictions after earlier potential miscarriages of justices were uncovered.

Fujitsu CEO Takahito Tokita refused to confirm if the company would return any of the money it earned from Horizon.