80 No. 2 of 2016] Constitution of Zambia (Amendment) (3) The law to be applied with respect to a pension benefit– (a) before the commencement of this Constitution, shall be the law that was in force immediately before the date on which the pension benefit was granted or the law in force at a later date that is not less favourable to that employee; and (b) after the commencement of this Constitution, shall be the law in force on the date on which the pension benefit was granted or the law in force at a later date that is not less favourable to that employee. Review of pension benefit and tax exemption 188. (1) A pension benefit shall be reviewed periodically to take into account actuarial assessments. Payment of pension benefits 189. (1) A pension benefit shall be paid promptly and regularly. (2) A pension benefit shall be exempt from tax. (2) Where a pension benefit is not paid on a person’s last working day, that person shall stop work but the person’s name shall be retained on the payroll, until payment of the pension benefit based on the last salary received by that person while on the payroll. PART XV DEFENCE AND NATIONAL SECURITY Principles relating to Defence Force and national security services 190. (1) The Defence Force and national security services shall— (a) be nationalistic, patriotic, professional, disciplined and competent; (b) be non-partisan; (c) not further the interests or cause of a particular organisation; and (d) not act against a political interest or cause permitted in this Constitution or as prescribed. (2) Clause (1) shall not prevent a member of the Defence Force and national security services from registering as a voter or voting in an election or a referendum. Status of Defence Force and national security services 191. be— The Defence Force and national security services shall (a) subordinate to civilian authority, as vested in the State organs; and