For those members that are interested in taking photographs in London are well aware of that photography has attracted the attention of the Police in relation to the Terrorism Act 2000, the link below provides advice from the Metropolitan Police to photographers
Officers have the power to view digital images contained in mobile telephones or cameras carried by a person
Officers do not have the power to delete digital images or destroy film at any point during a search.
From a personal point of view when I have been asked to provide identification , I saw no reason not to. My general approach when stopped is to be polite and explain what and why I am taking photographs. To date I have not been arrested or carted off the local nick for taking photographs.