The biggest data protection myth out there is that third party personal data cannot be disclosed under a subject access request that covers “mixed” personal data, i.e. information that contains personal data of more than one individual.
If I had €10 every time a data controller made this claim I wouldn’t need to write this update because I’d have already retired a rich man and would be sitting in my vineyard in the South of France enjoying the good life.
The reality is that there is no presumption against disclosure of third party personal data in a mixed access request. Obviously third parties have privacy rights which cannot be adversely effected but that doesn’t mean they have to consent to disclosure. A data controller has to balance competing interests and make a decision in line with the GDPR, that’s what the law says.
While it may be a difficult to decision to make in some circumstances, generally there should be no real issue since the GDPR facilitates the processing of others people’s personal data as long as it is lawful, responding to a subject access request is no different.
Data controllers are risking legal proceedings or complaints to the Data Protection Commission if they wrongly assume that all third party data must be purged when responding to subject access requests.
In many situations the rationale for the subject access request is to access information about other people, for example family members or professionals and in those circumstances data subjects may have a very strong legitimate interest in accessing mixed data.
B v General Medical Council
The English Court of Appeal considered this issue in the case of B v General Medical Council  EWCA Civ 1497 which concerned a request by a patient to access a report prepared by the General Medical Council after the patient had complained about his treatment by a doctor. The doctor objected to the release of the report saying it contained both his and the patient’s personal data and therefore his right of privacy prevented the report being released to his former patient.
The General Medical Council nevertheless decided that on balance the rights of the patient favoured releasing the report to him. The doctor successfully appealed to the High Court but that appeal was overturned in the Court of Appeal on the basis that there is no presumption in favour of refusing access to mixed data and the data controller is best placed to make that evaluation and in this instance had done so correctly and lawfully.
Data controllers need to take heed
This case shows that data controllers have a wide margin of discretion but nevertheless have to weigh up the competing interests when handling a subject access request for access to mixed personal data. There is no presumption that mixed data must be refused or that the third party data subject must consent to release.
Any data controller that handles a subject access request based on these presumptions risks litigation or a complaint to the Data Protection Commission.
This article was also published on LinkedIn