Judgment No CCZ 8/16 10 Const. Application No CCZ 48/15 excluded, by s 12(2) of Act No. 4 of 1993, in respect of any treaty or convention concluded before November 1993. Both Covenants are therefore binding upon Zimbabwe and fall into the category of treaties that must, in conformity with s 46(1)(c) of the current Constitution, be taken into account in interpreting the Declaration of Rights. The principal international instrument on the regulation of prisons is contained in the Standard Minimum Rules for the Treatment of Prisoners, which were adopted by a United Nations Congress in 1955 and subsequently approved by its Economic and Social Council in July 1957 and May 1977. The preamble to the Rules makes it clear that they are not intended to detail a model system of penal institutions. Rather: “They seek only, on the basis of the general consensus of contemporary thought and the essential elements of the most adequate systems of today, to set out what is generally accepted as being good principle and practice in the treatment of prisoners and the management of institutions.´ In relation to prisoners under sentence, the guiding principles are set out in Rules 56 to 64. In summary, they emphasise the following tenets: the prison system should not aggravate the suffering inherent in the deprivation of liberty; the prisoner should be able to lead a law-abiding and self-supporting life upon his return to society; the institution should seek to address the individual treatment needs of the prisoners; the institution should respect the dignity of prisoners as human beings; steps should be taken to ensure for the prisoner a gradual return to life in society; the treatment of prisoners should emphasise not their exclusion from the community, but their continuing part in it; the institution should detect and treat any mental or physical illnesses or defects that hamper