Alves, M.J.& Gonçalves,F. (2011) – As medidas de coacção no processo penal português. 1st Ed. Almedina. Coimbra

The growth of social security privatization requires rethinking the principles of subsidiarity and democratic participation of citizens in social life, obliging society to produce minimum security levels, through the carrying of self-protection measures. The complementarity (or cohesive relationship) between public and private security helps to rid police forces of certain tasks, so they can focus on core functions and skills: the field of crime prevention (in the strict sense), public order, intelligence, criminal investigation and international cooperation. Knowing in advance that it cannot increase the Police ad æternum, the State partially resigns its eminent dominant role in matters of security. The solution is to remove police forces’ duties, using the private security industry, and relying as far as possible on the principles of complementarity and subsidiarity in the pursuit of social security tasks.