Ex-postmaster Noel Thomas 'did not take missing cash'
Documents uncovered by the BBC suggest "operational errors" could have led to false accounting which saw a former north Wales postmaster jailed.
Noel Thomas, from Gaerwen, is one of dozens of postmasters who were prosecuted after having problems with the Post Office's "Horizon" computer system.
Documents obtained by BBC Panorama reveal it now accepts the losses could have been due to "operational errors".
The Post Office denies any wrongdoing.
BBC Panorama reporter John Sweeney spoke to Mr Thomas.