THE NELSON MANDELA RULES 29 order to encourage good conduct, develop a sense of responsibility and secure the interest and cooperation of prisoners in their treatment. Work Rule 96 1. Sentenced prisoners shall have the opportunity to work and/or to actively participate in their rehabilitation, subject to a determination of physical and mental fitness by a physician or other qualified health-care professionals. 2. Sufficient work of a useful nature shall be provided to keep prisoners actively employed for a normal working day. Rule 97 1. Prison labour must not be of an afflictive nature. 2. Prisoners shall not be held in slavery or servitude. 3. No prisoner shall be required to work for the personal or private benefit of any prison staff. Rule 98 1. So far as possible the work provided shall be such as will maintain or increase the prisoners’ ability to earn an honest living after release. 2. Vocational training in useful trades shall be provided for prisoners able to profit thereby and especially for young prisoners. 3. Within the limits compatible with proper vocational selection and with the requirements of institutional administration and discipline, prisoners shall be able to choose the type of work they wish to perform. Rule 99 1. The organization and methods of work in prisons shall resemble as closely as possible those of similar work outside of prisons, so as to prepare prisoners for the conditions of normal occupational life. 2. The interests of the prisoners and of their vocational training, however, must not be subordinated to the purpose of making a financial profit from an industry in the prison. Rule 100 1. Preferably, institutional industries and farms should be operated directly by the prison administration and not by private contractors.