Paula Vennells, the former CEO of the Post Office, will testify this week about the Horizon IT scandal, which led to the wrongful prosecution of over 900 sub-postmasters between 1999 and 2015 due to faulty software. Vennells, who led the Post Office from 2012 to 2019, has faced criticism for her handling of the investigation. She resigned in 2019, and recently handed back her CBE; she's scheduled to appear before the inquiry starting May 22.