From Stephen Lawrence to today's Taser revelations, Britain's forces of law and order have defiled the idea of the public sphere

"The police are the public and the public are the police," said the force's modern founder, Robert Peel, in the early 19th century. Never has a fundamental principle come to sound so hollow. Everything from the treatment of domestic violence victims and the appalling treatment of the Lawrence family to the Hillsborough campaign smears, undercover spying on...