hans solo wrote:so when do the people who prosecuted wrongly get charged
Although a good point, I think you are missing the bigger picture.
The Post Office is one of a select band of organisations who are allowed to prosecute criminal cases themselves, instead of going through the Crown Prosecution Service. But they are also the holders of all the data vital to those prosecutions. So in some trials, the PO is both the prosecutor and the expert witness. I think it is time that the Post Office had it’s right to prosecute criminal trials taken away. Making them go through the CPS would ensure that they are subject to a greater degree of challenge over their evidence before trials take place, and reduce the potential conflicts of interest inherent in the current set-up.
It also seems like a good time to review whether other organisations should be allowed to prosecute their own cases: Royal Mail, for instance.
In civil disputes with Sub-Postmasters, the Post Office controls both the data and the contract terms. Again, this gives them too much power. There needs to be an independent regulator of the contracts, and the NFSP either needs to be freed from its serfdom or abolished.
We should try to prosecute those responsible, but it is always hard to identify the single controlling mind. Changing the system is the best way of stopping it from happening again.