A Japanese technology giant is in the crosshairs of British lawmakers for building the faulty accounting software that led to what has been called the country's biggest-ever miscarriage of justice.

Fujitsu created the Horizon IT system that resulted in some 700 local post office managers being wrongly convicted for theft and false accounting between 1999 and 2005.

The U.K. government, which plans to exonerate all victims, has warned the company will be "held to account" if a public inquiry finds it guilty of wrongdoing.