Retrospective Operation of Law  In Maxwell on the Interpretation of Statutes, 12th Edn. the statement of law in this regard is stated thus : “Perhaps no rule of construction is more firmly established than thus — that a retrospective operation is not to be given to a statute so as to impair an existing right or obligation, otherwise than as regards matters of procedure, unless that effect cannot be avoided without doing violence to the language of the enactment. If the enactment is expressed in language which is fairly capable of either interpretation, it ought to be construed as prospective only. the rule has, in fact, two aspects, for it. “involves another and subordinate rule, to the effect that a statute is not to be construed so as to have a greater retrospective operation than its language renders necessary.” In Francis Bennion’s Statutory Interpretation, 2nd Edn, the statement of law is stated as f ....