An ambitious plan to digitalize the courts was meant to remove the need for hundreds of thousands of paper documents. But File on 4 Investigates has discovered an IT system, introduced as part of a £1bn project, has been plagued with technical faults - causing crucial information to go missing, be overwritten, or appear lost.

The government body that runs the courts in England and Wales has now checked hundreds of thousands of benefit and child support appeals to identify if any were affected by missing evidence. But sources say the IT bug was known about for years before action was taken.

Original journalism by Alys Harte. Reporter: Datshiane Navanayagam. Producers: Lorna Acquah, Fergus Hewison. Editor: Tara McDermott. Technical Producer: Nicky Edwards. Production Co-ordinator: Tim Fernley.