A lot of criticism of the courts here - much of which is probably reasonable. I wonder though if one element is that post masters were of course prosecuted ind

A lot of criticism of the courts here - much of which is probably reasonable. I wonder though if one element is that post masters were of course prosecuted individually, and the evidence mounted against them may have looked convincing on an individual basis - with the courts not having the time or the resources to mount a full scale investigation into the validity of the claims made by the post office. Only when looked at in aggregate did the position look absurd - 700 or so postmasters breaking the law in this way out of 12,000 or so post offices. I suspect that it's rare for courts to perform a probabilistic assessment of the likelihood of an offence occurring. The only people with an overview of the situation were post office management and they chose to cover it up.