Former Post Office CEO Paula Vennells will testify at the ongoing Post Office Horizon IT scandal inquiry.

Vennells led the Post Office from 2012 to 2019 and faces accusations of a cover-up by subpostmasters during her tenure.

Key issues include her knowledge of the faulty Horizon system, false evidence in prosecutions, and her interactions with IT staff.

Subpostmasters hope her testimony will clarify wrongful convictions that occurred.

The Metropolitan Police is investigating potential fraud offenses, with Fujitsu experts under scrutiny for perjury.

Despite the investigation's gravity, no arrests have been made since the inquiry started in January 2020.

Public trust in the Post Office has significantly declined, with subpostmasters still awaiting full compensation.

Vennells has expressed remorse for the harm caused and is committed to helping victims cope with the scandal's mental health impact.

Calls have been made to revoke her CBE, which she returned in 2019.

Several victims, including Martin Griffiths, Fiona McGowan, Peter Huxham, and Louise Mann, died by suicide.

The Post Office has issued an apology and a settlement, with the Samaritans helpline available for support.