`Unjust enrichment' means retention of a benefit by a person that is unjust or inequitable.
Stated simply, `Unjust enrichment' means retention of a benefit by a person that is unjust or inequitable. `Unjust enrichment' occurs when a person retains money or benefits which in justice, equity and good conscience, belong to someone else.
The doctrine of `unjust enrichment', therefore, is that no person can be allowed to enrich inequitably at the expense of another. A right of recovery under the doctrine of `unjust enrichment' arises where retention of a benefit is considered contrary to justice or against equity.
The juristic basis of the obligation is not founded upon any contract or tort but upon a third category of law, namely, quasi-contract or the doctrine of restitution.
In the leading case of Fibrosa v. Fairbairn, [1942] 2 All ER 122, Lord Wright stated the principle thus :
