Illegality and unjustified enrichment

This chapter reviews the different approaches to enrichment recovery following a finding that a contract is illegal found in the PECL, the Unidroit Principles and (differently) in the DCFR. Thanks to Patel v Mirza, English and (probably) Scots law now provide a testbed for the policy-based approach to questions of illegality and unjustified enrichment found in the DCFR. This suggests, however, that the DCFR's approach of making illegality primarily a defence to an enrichment claim is inappropriate. A more coherent approach would be to make the sole focus of any defence whether or not retention of the enrichment is contrary to the policy of the law infringed, rather than starting from the position that reversal of the enrichment must not be so contrary. Otherwise, it is submitted that in principle enriching performances rendered under an illegal contract should be reversible, whether under the general enrichment regime (by renewal of the condictio ob causam turpem vel iniustam causam in Scotland, most likely, or extension of the condictio causa data causa non secuta) or, perhaps, the unified restitutionary regime for failed contracts in general proposed in the Jansen/ Zimmermann Commentary on European Contract Laws.