On 27th May a user of our WhatDoTheyKnow website raised an FOI request to Islington Borough Council. On the 26th June the council responded to the FOI request by sending three Excel workbooks. Unfortunately, these contained a considerable amount of accidentally released, private data about Islington residents. In one file the personal data was contained within a normal spreadsheet, in the two other workbooks the personal data was contained on four hidden sheets.
...
The personal data released by Islington Borough Council relates to 2,376 individuals/families who have made applications for council housing or are council tenants, and includes everything from name to sexuality. It is for the ICO, not mySociety, to evaluate what sort of harm may have resulted from this release, but we felt it was important to be clear about the details of this incident.