The government has given extra powers to the Horizon IT system investigation.
A woman from West Byfleet, who was pregnant when she was jailed, was among 39 former Post Office workers wrongfully imprisoned for fraud and cleared last month.
Postal Affairs Minister and Sutton MP Paul Scully says the impact of the IT failure “cannot be overstated”.
Seema Malhotra, Feltham MP and Shadow Business minister, says the steadfast belief in the computer system ruined people’s lives.