The MI5 wants access to the Oyster travel card database to be able to trawl it for possible suspects. Today they may demand the data to track specific individuals under investigation but the change will allow them to search for unknown suspects based on “suspicious” travel patterns.
Systems such as these will make sure that people with strange travel patterns around the metropolis will be seen as being suspicious in general. If you are an oddball (in your movements around the city) you will now be able to be classed as a potential threat to national security.
Another step in the loss of anonymity, not to mention the fact that taking the scenic route to work in the morning suddenly becomes more ominous…
More at the Guardian.