I don't know the full details of how the judges operated during the prosecutions, but one of the bizarre details is that the post office has the oldest prosecut

I don't know the full details of how the judges operated during the prosecutions, but one of the bizarre details is that the post office has the oldest prosecution and investigation team in the world, predating the police force, dating back to highwaymen robbing postal services on horseback. In other words, the post office executives seem to have made a policy decision around these financial discrepancies, the post office managers gathered evidence on their behalf under the guise of helping their employees, and the post office prosecution team prosecuted them in court. Very little unbiased external opinion was brought in. Even the police seemed to have decided early on that they didn't have jurisdiction in the post office for the above reasons. Its an extremely bizarre detail that, as a UK resident, I had no idea about until these recent revelations.