The Post Office has conceded appeals by former sub-postmasters to overturn convictions linked to the Horizon accounting scandal.
The company said it is not opposing 44 of the appeals in which it acted as prosecutor.
Sub-postmasters were wrongly accused of theft, fraud and false accounting after the Horizon IT system was introduced to Post Office branches in 1999.
Post Office chairman Tim Parker said: “I am sincerely sorry on behalf of the Post Office for historical failings which seriously affected some postmasters.
“Post Office is resetting its relationship with postmasters with reforms that prevent such past events ever happening again.
“Post Office wishes to ensure that all postmasters entitled to claim civil compensation because of their convictions being overturned are recompensed as quickly as possible.
“Therefore, we are considering the best process for doing that.”
In addition to full co-operation with the Criminal Cases Review Commission’s review, the Post Office said it has set up an extensive disclosure exercise, by external criminal law specialists, to identify material which might affect the safety of any relevant historical prosecutions.
Solicitors acting for some of the sub-postmasters said it was a “landmark moment”.