Unjust Enrichment in UK Law

My Lords, there is no general doctrine of unjust enrichment recognised in English law. It is a convenient way of describing a transfer of rights from one person to another, without assignment or assent of the person from whom the rights are transferred and which takes place by operation of law in a whole variety of widely different circumstances.

But I think it should be recognised that one is here concerned with a restitutionary remedy and that the appropriate questions are therefore, first, whether the defendant would be enriched at the plaintiff's expense; secondly, whether such enrichment would be unjust and thirdly, whether there are nevertheless reasons of policy for denying a remedy. But I think it should be recognised that one is here concerned with a restitutionary remedy and that the appropriate questions are therefore, first, whether the defendant would be enriched at the plaintiff's expense; secondly, whether such enrichment would be unjust and thirdly, whether there are nevertheless reasons of policy for denying a remedy.

It is a means by which the court regulates the legal relationships between a plaintiff and a defendant or defendants in order to prevent unjust enrichment. It is a means by which the court regulates the legal relationships between a plaintiff and a defendant or defendants in order to prevent unjust enrichment.

As Professor Birks pointed out, the availability of money to use is not unequivocally enriching in the same degree as the receipt of money: Unjust Enrichment, 2nd ed, p 53. It is an imperfect way of measuring the time value of what was received prematurely. Restitution requires that the entirety of the time value of the money that was paid prematurely be transferred back to Sempra by the Revenue.

If, applying these principles, the agreement is found to be valid and is therefore not set aside, questions of 'knowing receipt' by B do not arise. So far as B is concerned there can be no question of A's assets having been misapplied. B acquired the assets from A, the legal and beneficial owner of the assets, under a valid agreement made between him and A. If, however, the agreement is set aside, B will be accountable for any benefits he may have received from A under the agreement.

Having considered the wide ranging material put to me by Mr Matthias (wide ranging despite the relatively short period of time that this case took—argument on all issues took less than a day), it seems to me that it has not been established that the authorities have yet moved to a position in which it can be said that there is a freestanding claim of unjust enrichment in the sense that a claimant can get away with pleading facts which he says leads to an enrichment which he says is unjust.