Thank you for your email received by us on 8 September 2017 asking for an anonymised data set from the London Underground Wifi Tracking Trial which took place in 2016.

Your request has been considered in accordance with the requirements of the Freedom of Information Act and our information access policy. I can confirm that we hold the information you require. You asked for:

the full dataset of anonymized data for the London Underground Wifi Tracking Trial

This request is to ask for the release of all of this data into the public domain and should have enough information supporting to allow data analysis on this dataset.

It should be provided in whatever form, along with any appropriate descriptive texts that was passed to the Chief Data Officer of TfL

Part of our controls to protect this data and prevent an individual being identified was that all the Media Access Control (MAC) address information collected from wifi-enabled devices during the pilot was automatically pseudonymised and encrypted to prevent the identification of the original MAC address and associated device. The data is stored in an encrypted and segregated area of a secure network. The data collected during the pilot was not shared with any third parties or matched against any other data sets for the purpose of identifying or monitoring individuals.

Although the MAC address data has been pseudonymised, personal data as defined under the Data Protection Act 1998 (DPA) is data which relate to a living individual who can be identified from the data, or from those data and other information which is in the possession of, or is likely to come into the possession of, the data controller. Given the possibility that the pseudonymised data could, if it was matched against other data sets, in certain circumstances enable the identification of an individual, it is personal data. The likelihood of this identification of an individual occurring would be increased by a disclosure of the data into the public domain, which would increase the range of other data sets against which it could be matched. As personal data it is therefore exempt from disclosure under section 40(2) of the FOI Act, because disclosure of the personal data would be a breach of the DPA, specifically the first principle of the DPA which requires all processing of personal data to be fair and lawful. It would not be fair to disclose this personal information when the individuals have no expectation it would be disclosed and TfL has not satisfied one of the conditions of Schedule 2 of the Data Protection Act which would make the processing ‘fair’.

If this is not the information you are looking for, or if you are unable to access it for any reason, please do not hesitate to contact me.

Please see the attached information sheet for details of your right to appeal as well as information on copyright and what to do if you would like to re-use any of the information we have disclosed.

Yours sincerely

Jasmine Howard
FOI Case Officer
Information Governance
Transport For London