Enlarge / Paul Patterson, co-CEO of Fujitsu's European division, testifies for a public inquiry in London on January 19, 2024. (credit: Getty Images | AFP)

Fujitsu software bugs that helped send innocent postal employees to prison in the UK were known "right from the very start of deployment," a Fujitsu executive told a public inquiry today.

"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," said Paul Patterson, co-CEO of Fujitsu's European division.

That goes back to 1999, when the Horizon software system was installed in post offices by Fujitsu subsidiary International Computers Limited. From 1999 to 2015, Fujitsu's faulty accounting software aided in the prosecution and conviction of more than 900 sub-postmasters and postmistresses who were accused of theft or fraud when the software wrongly made it appear that money was missing from their branches.