The CPS, and equivalents in Scotland, brought around a third of the wrongful prosecutions.
The barristers the CPS employs to bring prosecutions are the same barristers used by the Post Office, using the same courts and the same judges.
This scandal just shines a light on how impossible the criminal justice system is for ordinary people with more limited means. Bates vs PO only happened because they managed to find 555 claimants (500 being the minimum their funders needed to risk it).
There was a case settled in 2003 because the court appointed a single independent expert to act for both sides and he pointed out all the holes in the Post Office case. That should have been the end of it. But they made the Cleveleys subpostmaster sign a confidentiality agreement, slandered the expert, and carried on prosecuting.