In countries where the ‘rule of law’ applies, there is usually a dislike of legislation which has retrospective effect. In this brief post, I do not seek to discuss in any detail the merits or otherwise of the arguments for or against retrospective legislation, save to say that with regard to legal certainty, it is important both for individual citizens and business enterprises as well as other legal entities that they can assess the legality and legal effects of a planned action before instituting such action. They ought not be exposed to the risk of burdensome, ex post changes to the legal rules.
This is perhaps especially true when it comes to the question of newly introduced or sharpened penalties or similar sanctions, as well as changes in tax or fee legislation making it more rigid, or prohibitions and injunctions by the authorities, aimed at actions or behaviours that were allowed when they were adopted.
