Whenever a device accesses a communications network, small packets of data related to that device’s activities are logged on the systems of the operator responsible for the network. This ‘metadata’ is necessary for the network to function effectively: for example, in order to route a call to a mobile phone, the network needs to know the mobile network cell site that the device is connected to. Operators also need to store some metadata – such as information about call duration, location and destination – to ensure customers are billed correctly.
This metadata can be thought of as the address on the outside of an envelope; the communications content (which can be accessed via a lawful interception demand, as explained above) can be thought of as the letter inside the envelope.
It is possible to learn a great deal about an individual’s movements, interests and relationships from an analysis of metadata and other data associated with their use of a communications network, which we refer to generally as ‘communications data’ – and without ever accessing the actual content of any communications.