Fujitsu has a moral obligation to help compensate UK postmasters wrongly convicted because of a bug in its accounting software, its European director said on Tuesday.
Paul Patterson apologised to those affected by the glitches in its Horizon system that saw some 700 local post office managers accused of theft and false accounting between 1999 and 2005.
Some were jailed, others went bankrupt and lost their homes or their health, while four people took their own lives and dozens since exonerated died without seeing their names cleared.
"Fujitsu would like to apologise for our part in this appalling miscarriage of justice," Patterson, who joined the company in 2019, told lawmakers probing the scandal, which has been called the UK's biggest miscarriage of justice.
"We were involved from the very start. We did have bugs and errors in the system and we did help the post office in their prosecutions of the subpostmasters. For that we are truly sorry."
The long-running saga has hit headlines since the broadcast of a television drama about the subpostmasters' ordeal, generating a wave of sympathy and outrage.
Patterson told a parliamentary committee that Fujitsu, which assisted the Post Office in prosecutions using flawed data from the software, had a moral obligation to redress the "travesty".
"I am personally appalled by the evidence that I have seen and what I saw on the television drama," he said.
"We have a moral obligation," he said. "We also expect to sit down with government to determine our contribution to that redress."
Fujitsu -- which has headquarters in Tokyo -- is one of the world's largest IT services providers, with annual revenues of around $27 billion.
It provides IT services to multiple UK government departments including the interior, foreign, and environment ministries.
The UK government has warned Fujitsu that it will be "held to account" if a public enquiry finds it guilty of wrongdoing, and has set aside GBP1 billion in compensation for thousands affected in the case.
Some MPs want billions of dollars of government contracts with Fujitsu to be re-examined in the light of the scandal.
But Post Office's chief executive Nick Read told the lawmakers the scandal was "an extremely complex situation".
He said he wanted the inquiry to be given "every opportunity" to understand "what exactly happened, who was accountable" and what to do next.
