Legal Irritants: Good Faith in British Law or How Unifying Law Ends Up in New Divergencies

Legal transplant is an unsatisfactory metaphor for describing the transfer of legal rules from one legal system to another. Instead, the metaphor of legal irritant better describes the impact on the legal system, and then a distinction between tight and loose coupling between law and its social context better explains the trajectory of social effects. The example of the importation of the civil law concept of good faith into British law illustrates the co‐evolving trajectories of the legal system and tightly coupled social systems which instead of furthering harmonisation of laws produces new divergences as their unintended consequences.