ABSTRACT
It is generally acknowledged that the development of the English law of unjust enrichment was held back because of its refusal to recognise a defence of change of position. In the absence of any such defence, it was necessary to restrict the availability of restitution at the liability stage. Thus, as we have seen, English law until recently refused to allow restitution based solely upon the claimant’s mistake of law. The liability mistake rule can be explained in the same way as can the requirement that a failure of consideration had to be total if it was to trigger restitution.
