Ubiquitous personal communication technologies are here to stay. Because of exponentially falling data storage costs, two contrasting states of society can be envisaged. The default will be either that individuals determine whether and when their history is recorded, subject to exceptions, or data will exist about everyone all the time. This is the policy choice between data retention and preservation, and it is a sharp dichotomy.
Over two decades the UK has been in the vanguard of a core group of five European countries seeking systematic Internet surveillance. A blanket retention regime gives law-enforcement an “Internet Tardis” to go back in time and find out retrospectively what anyone was thinking about, whom they were talking to, and where they were. The dichotomy between retention and preservation is really about whether we want to give government such a “time machine” to scrutinize everyone’s past behaviour without prior reason.