A single series (OBS 1) consisting of finding aids to records currently or previously held in the Public Record Office, which are no longer current for one of the following reasons:
1. The records to which they relate have been transferred out of the Public Record Office to other places of deposit.
2. The records to which they relate have been destroyed, either under permission from the Lord Chancellor, or accidentally, eg by fire.
3. The records to which they relate have been transferred to other series, and lists showing the new archival references have been produced.
4. The records to which they relate have been given new references within the same series, and hence new lists have been produced.
5. Revised lists have been produced, but additional information appears on the original versions, which may still be of interest to some readers.