A mandatory rule... is an imperative provision of law which must be applied to an international relationship irrespective of the law that governs that relationship. To put it another way: mandatory rules of law are a matter of public policy (order public) and moreover reflect a public policy so commanding that they must be applied even if the general body of law to which they belong is not competent by application of the relevant rule of conflict of laws. It is the imperative nature per se of such rules that make them applicable. One is thus led to conclude that there is an ‘approach to mandatory rules of law’ different from the classical method of conflict of laws. In matters of contract, the effect of a mandatory rule of law of a given country is to create an obligation to apply such a rule, or indeed simply a possibility of so doing, despite the fact that the parties have expressly or implicitly subjected their contract to law of another country.