'Initial investigations have now established some of what happened. A security source has told the Belfast Telegraph that the request came to the FoI unit and was passed to HR. The source said it was at this point that the data — known as the 3C Personnel List — entered the spreadsheet.
A second source said that even superintendents in charge of whole districts do not have access to the material.
The list, by now not immediately visible when the document was opened, but in a second tab in the spreadsheet, then went to another part of HR for “quality assurance” before being sent outside HR to the FoI unit.
It then sent the data to the PSNI communications department which takes an interest in material which might interest journalists — ironically, given what was to follow, it missed the biggest data breach story the UK has ever seen.
The data returned to the FoI unit, which issued it. But there was a final bulwark which ought to have made this release difficult. The PSNI has a security system which prevents email attachments being sent to external addresses without first being checked.
Even though this was an Excel spreadsheet whose enormous size — 1.5mb — indicated it contained gargantuan volumes of information, that system either failed to raise an alarm, or the alarm was ignored.
That meant that five police processes failed to spot that something was seriously amiss. When put to the PSNI yesterday, it did not dispute that is what happened.'
https://archive.ph/Gb2m1
Unless you honestly believe IRA/Sinn Féin sympathizers were involved at each stage, it appears only to be several folk not doing their jobs properly.