Police systems around the world display a diversity of institutional designs. In comparative perspective, national police systems are distinguished by (a) the level of fragmentation, which may be local, regional or federal; (b) the diversity of responsibilities conferred upon them; (c) their degree of professionalism; (d) their level of accountability; and (e) their degree of autonomy from the political system. Th e form that each system takes is generally evolutionary rather than planned. Police systems are products of the history of each country, refl ecting their singular political and social dynamic (Bayley 1975).