It has to be borne in mind that this goes with an ever-widening power of arrest.

The most interesting and depressing thing about the report is that the PM is urging police to use the power. He apparently wants a large database for its own sake, whereas--since it costs money, takes time, will be unpopular with suspects, and physically hazardous if resisted--the police left to their own devices will probably only use it in situations where they feel it will be worthwhile.