Between 1685 and 1720, twenty-nine men were caught impersonating law officers in Westminster. Though these cases may seem small in number, they represent the most common type of imposture in this period. This article argues that the impersonation of officials is an important window into the unique nature of identity and law enforcement in early eighteenth-century London. The metropolis had grown to the point where parish constables might not be recognized, and the low origins and reputed venery of many officials made this an appealing avenue for impostors. In an anonymous urban environment before photo identification, people looked at dress, demeanor, and symbols of office to determine identity, all of which worked to the advantage of these Westminster impostors.