Data Protection Commissioner
Data Protection Commissioner

CASE STUDY 2/00

Department of Education & Science – use of trade union membership subscription data to withhold pay – fair obtaining and processing – specified purpose – compatible use – purpose as described in register entry

A group of teachers, all members of a particular trade union, was engaged in industrial action against the Department of Education & Science. The Department decided to withhold pay from the individuals for days on which, arising from their industrial action, the individuals were not – in the view of the Department – properly performing their work duties. In order to do this, the Department used the payroll database to identify those individuals who were members of the trade union, and pay was withheld from those individuals.

A number of the teachers affected complained to me that the use of their personal data in this way was contrary to the Data Protection Act. Many of the complainants said it was wrong that information held by the Department in order to facilitate the deduction-at-source of union subscriptions should be used for this new purpose, against their interests and without their consent or authorisation. Some individuals pointed out that, while they were members of the trade union, they had in fact been working normally on the days in respect of which the pay deductions were made.

I raised this matter with the Department, which responded promptly and seriously, and it was agreed that no further deductions would be made pending the resolution of the data protection issues. For my part, I made it plain that my investigation had nothing whatever to do with the substantive industrial relations issue of whether the Department had the right to withhold pay, but only with the question of whether the means used to achieve this end were compatible with data protection law.

Section 2 of the Act provides that personal data "shall have been obtained, and shall be processed, fairly". That section also requires that the personal data "shall be kept only for one or more specified and lawful purposes", and "shall not be used or disclosed in any manner incompatible with that purpose or those purposes". Taken together, these provisions amount to a general requirement that individuals should be made aware, at the time of the collection of their personal data, of the purposes to which their data will be put, and that the data may not subsequently be used for different purposes, without first obtaining the authorisation of the data subjects. I share the view consistently and clearly expressed by my predecessors that this simple principle of fairness and transparency is the very bedrock of data protection law.

In the case in question, I noted that the complainants had provided their trade union membership details on a special authorisation form, titled "Authorisation of Deduction of Subscription from Salary". The wording of the form simply mandated the Department to deduct union membership subscriptions from salary, and forward the moneys to the trade union. The form made no mention about other uses by the Department of the individual's trade union membership data. In these circumstances, I was satisfied that the purpose for which the data had been obtained by the Department, and for which the data were kept, was quite plain; and that this purpose did not encompass the use to which the Department had actually put the data.

Against this, the Department argued that the terms of its register entry were sufficient to authorise the use of the personal data in these cases. One of the Department's entries in the public register described the "purpose" of holding personal data as: "Administration of teaching staff for second level schools." The data in question were described in the register entry as including "payment matters." The Department argued that the "specified and lawful purpose" referred to in section 2 of the Act must be determined by reference to the purpose set out in the register entry. Since the withholding of the complainants' pay came within the scope of the broad purpose "administration of teaching staff", the Department argued that its use of personal data was "not incompatible" with that broad purpose, and so no contravention of the Act was involved.

This argument was not one I could accept. I explained that the "specified and lawful purpose" mentioned in section 2 of the Act is to be determined by reference to the circumstances in which data have been obtained. Since the personal data relating to trade union membership had been obtained via a deduction-at-source mandate form, and accepted on that basis, then the "specified and lawful purpose" for holding those particular data related to the deduction-at-source facility, not any other purpose. This purpose should have been reflected in the Department's register entry. In fact, the Department had included a much broader description of purposes in its register entry. The Department could not legitimately rely upon this broad description to displace the actual purpose for holding the union membership data, or to infer the existence of new "specified and lawful purposes" which were unknown and unthought-of when the data had been obtained. As my predecessor commented when this argument was discussed in a previous case (case study 8 from the 1998 Annual Report):

The purpose of including details in the Register entry is to describe, in a publicly accessible form, the outer limits of what the data controller may do with personal data, not to provide a 'back door' that would allow a data controller to circumvent its basic data protection responsibilities.

I accordingly decided that the Department had breached data protection law by using the complainants' trade union membership data as it had.

Since this case was concluded, I have contacted the heads of all Government Departments, advising them to ensure that the details recorded in their public register entries are appropriately detailed, meaningful and specific. In this way, there can be clarity on all sides regarding the uses to which personal data may legitimately be put.