R (on the application of TD) v Metropolitan Police Commissioner [2014] EWCA Civ 585, [2014] All ER (D) 37 (Jun)
Retention of personal information about individuals by authorities of the state, including the police, had a strategic effect on the balance of power between state and citizen. It might enlarge the state’s effective powers and it might limit the confident security of the citizen. That was a prickly path and the constitution needed to be wary of it. For that reason, quite aside from the consideration of Art 8 of the European Convention on Human Rights in individual cases, such retention of information always stood in need of justification. It might, of course, be well justified, but that general point was an important one.