34 The presumption against retrospective operation is common law based. In this State, it has some statutory backing through the enactment of s 37(1)(c) of the Interpretation Act 1984 (WA). That section provides that the repeal of an enactment does not, unless the contrary intention appears, 'affect any right, interest, title, power or privilege created, acquired, accrued, established or exercisable or any status or capacity existing prior to the repeal'. The courts have generally regarded the statutory test (uniformly expressed in most jurisdictions) as not leading, relevantly, to any different result than the common law: Robertson v City of Nunawading [1973] VicRp 81; [1973] VR 819, 827 (Winneke CJ, Gowans & Starke JJ); Carr v Finance Corporation of Australia Ltd [1982] HCA 43; (1982) 150 CLR 139, 152. The statutory provision is applicable only in the case of the repeal of an 'enactment', defined in s 5 of the Interpretation Act as meaning 'a written law or any portion of a written law'. There is, for present purposes, no repeal of any relevant enactment (the 'double jeopardy' principle having been a creation of the common law) and the question is consequently whether the common law presumption must be applied.