Combines and updates three earlier books: Behind the blue lamp: policing north and east London by Peter Kennison and David Swinden (2003); More behind the blue lamp: policing south and south-east London by David Swinden, Peter Kennison and Alan Moss (2011); and Discovering more behind the blue lamp: policing central, north and south-west London by Peter Kennison, David Swinden and Alan Moss (2014).