8.1 In recent years the law of restitution and unjust enrichment1 has assumed increased importance in commercial litigation: the English courts have handed down a number of significant judgments developing this area of the law,2 and the last 20 years have seen a deluge of academic literature on the law of unjust enrichment and restitution. A number of theories have been advanced in an attempt to explain the case law.3 This area of law even has its very own US-style ‘Restatement’.4