It used to be the case that anything that was not illegal was permitted. Now it seems that anything not explicitly authorised is forbidden. These stop and search/account powers erode the relationship between individuals and the state, and lead to a culture of fear. People should be free to go about their daily business without interference from an overpowering Police force.
The current practice of Police officers stopping law-abiding members of the public and demanding information is, in my opinion, unjust and repressive. In particular, the stopping of people innocently engaged in photography for whatever reason is of great concern. I suggest that these powers are removed altogether, and that Police can only formally request information if there is genuine suspicion of criminal activity.