This Practice Note considers defences to a claim for restitution for unjust enrichment. For guidance on establishing such a claim, see Practice Note: Restitution for unjust enrichment—elements of the claim.

There are a number of defences that should be considered when faced with a restitutionary claim for unjust enrichment. Essentially, these defences are available where it is either impossible to restore the claimant to the original position prior to the enrichment, or it would be unjust to do so. They are:

1. •

   change of position renders restitution inequitable

2. •

   ministerial receipt

3. •

   bona fide purchaser for value

4. •

   estoppel to defeat a claim of unjust enrichment

5. •

   impossibility of counter-restitution can defeat a claim for unjust enrichment

6. •

   loss suffered is passed on

7. •

   illegality and incapacity of the underlying transaction (public policy)

8. •

   limitation