Fujitsu, the company whose faulty computer accounting system resulted in the wrongful conviction of hundreds of Post Office branch managers across the U.K., has apologized to the victims for its role in the country’s biggest ever miscarriage of justice and said it was long aware that the software had bugs.

Lawmakers are trying to get to the bottom of one of Britain’s gravest injustices and are questioning bosses of the Post Office and Fujitsu.

Britain’s Prime Minister Rishi Sunak says he will introduce measures to overturn the convictions of more than 900 post office branch managers who were wrongly accused of theft or fraud because of a faulty computer system.