BoingBoing has an excert from a pretty terrifying letter written by Jacqui Smith, the British Home Secretary, in response to some questions about the right to take pictures in public places. After confirming that there is no law against this practice she goes on to state:
“However, the Home Secretary adds that local restrictions might be enforced. ‘Decisions may be made locally to restrict or monitor photography in reasonable circumstances. That is an operational decision for the officers involved based on the individual circumstances of each situation.”
So, it’s legal but any cop can stop you if they think, at the moment, they don’t want you to take pictures. Like, if they’re harrassing an innocent person or using excessive force in an arrest. For instance.