You do not have to delete the pictures you have taken in a common, public space, even if asked. You have the basic right to record your environment in public -

You do not have to delete the pictures you have taken in a common, public space, even if asked. You have the basic right to record your environment in public - this is to ensure that people are able to collect evidence in the case of crimes being committed in the public sphere, and its how - for example - bank cameras work.