16 Judgment No. CCZ 2/18 Constitutional Application No. CCZ 86/15 the rule of law and is the most important practical constraint on retrospective civil legislation. Statutes should be so construed as to prevent them from operating retrospectively, unless the Legislature expresses the intention that the statute operates retrospectively in sufficiently clear and unambiguous language. In that case, the statute is effective according to its terms. Clarity and unambiguity of legislation are requirements of the principle of legality which is an aspect of the rule of law. A number of reasons have been suggested as bases for the hostility to retrospective legislation. The most fundamental reason why retrospective legislation is said to be suspect stems from the principle that a person should be able to plan his or her conduct with reasonable certainty of the legal consequences. Closely allied to this factor is mankind’s desire for stability with respect to past transactions. To the extent that statutory law should serve as a guide to individual conduct, the purpose is thwarted by retrospective enactments. See Charles B Hochman “The Supreme Court and the Constitutionality of Retroactive Legislation” 73 Harv. L. Rev. 692 (1960) pp 692-693. It must be emphasised that the presumption against retrospectivity of a statute applies in the absence of clear evidence of the intention of the Legislature to have the civil legislation operate retrospectively. The reason is that the objections to retrospective statutes are neither totally absent from prospective legislation nor are they totally persuasive. Where the statute expressly provides that it operates retrospectively, the presumption is rebutted and falls away. There is no question of interpretation. See Curtis v Johannesburg Municipality 1906 TS 308 at 311; Nkomo and Anor v Attorney-General and Others 1993 (2) ZLR 422 (S); Zimbabwe Phosphate Industries Ltd v Elias Matora & Others 2005 (2) ZLR 233 (S).