A quasi-contract is a fictional contract recognised by a court. The notion of a quasi-contract can be traced to Roman law and is still a concept used in some modern legal systems.
In laws of equity, unjust enrichment occurs when one person is enriched at the expense of another in circumstances that the law sees as unjust. Where an individual is unjustly enriched, the law imposes an obligation upon the recipient to make restitution, subject to defences such as change of position. Liability for an unjust enrichment arises irrespective of wrongdoing on the part of the recipient. The concept of unjust enrichment can be traced to Roman law and the maxim that "no one should be benefited at another's expense": nemo locupletari potest aliena iactura or nemo locupletari debet cum aliena iactura.
The law of restitution is the law of gains-based recovery, in which a court orders the defendant to give up his gains to the claimant. It should be contrasted with the law of compensation, the law of loss-based recovery, in which a court orders the defendant to pay the claimant for their loss.
A constructive trust is an equitable remedy imposed by a court to benefit a party that has been wrongfully deprived of its rights due to either a person obtaining or holding a legal property right which they should not possess due to unjust enrichment or interference, or due to a breach of fiduciary duty, which is intercausative with unjust enrichment and/or property interference. It is a type of implied trust.
Fibrosa Spolka Akcyjna v Fairbairn Lawson Combe Barbour Ltd[1942] UKHL 4 is a leading House of Lords decision on the doctrine of frustration in English contract law.
The English law of unjust enrichment is part of the English law of obligations, along with the law of contract, tort, and trusts. The law of unjust enrichment deals with circumstances in which one person is required to make restitution of a benefit acquired at the expense of another in circumstances which are unjust.
Change of position is a defence to a claim in unjust enrichment which operates to reduce a defendant's liability to the extent to which his or her circumstances have changed as a consequence of an enrichment.
Lipkin Gorman v Karpnale Ltd[1988] UKHL 12 is a foundational English unjust enrichment case. The House of Lords unanimously established that the basis of an action for money had and received is the principle of unjust enrichment, and that an award of restitution is subject to a defence of change of position. This secured unjust enrichment as the third pillar in English law of the law of obligations, along with contract and tort. It has been called a landmark decision.
Philip Collins Ltd v Davis [2000] 3 All ER 808 is an English unjust enrichment case, an example of a restitution claim and the change of position defence.
The English law of Restitution is the law of gain-based recovery. Its precise scope and underlying principles remain a matter of significant academic and judicial controversy. Broadly speaking, the law of restitution concerns actions in which one person claims an entitlement in respect of a gain acquired by another, rather than compensation for a loss.
Tracing in English law is a procedure to identify property that has been taken from the claimant involuntarily. It is not in itself a way to recover the property, but rather to identify it so that the courts can decide what remedy to apply. The procedure is used in several situations, broadly demarcated by whether the property has been transferred because of theft, breach of trust, or mistake.
BP Exploration Co (Libya) v Hunt [1983] 2 AC 352 is an English contract and unjust enrichment case, concerning the frustration of an agreement.
Westdeutsche Landesbank Girozentrale v Islington LBC[1996] UKHL 12 is a leading English trusts law case concerning the circumstances under which a resulting trust arises. It held that such a trust must be intended, or must be able to be presumed to have been intended. In the view of the majority of the House of Lords, presumed intention to reflect what is conscionable underlies all resulting and constructive trusts.
Foskett v McKeown[2000] UKHL 29 is a leading case on the English law of trusts, concerning tracing and the availability of proprietary relief following a breach of trust.
Trustee of FC Jones and Son v Jones[1996] EWCA Civ 1324 is an English unjust enrichment law case, concerning to what extent enrichment of the defendant must be at the expense of the claimant.
Kingstreet Investments Ltd v New Brunswick [2007] 1 SCR 3 is a Canadian unjust enrichment case, concerning to what extent enrichment of the defendant must be at the expense of the claimant.
Relfo Ltd v Varsani [2014] EWCA Civ 360 is an English unjust enrichment law case, concerning to what extent enrichment of the defendant must be at the expense of the claimant.
The local authorities swaps litigation refers to a series of cases during the 1990s under English law relating to interest rate swap transactions entered into between banks and local authorities. The House of Lords ruled that such transactions were unlawful. As a result of the decision over 200 separate actions were filed as hundreds of interest rate swap contracts had to be unwound by the courts at great expense.
Barclays Bank Ltd v W J Simms, Son and Cooke (Southern) Ltd [1980] 1 QB 677, [1979] 3 All ER 522 was a decision of the High Court of Justice relating to the recovery of a payment mistakenly made by a bank after the customer had countermanded the cheque.
Lloyds Bank plc v Independent Insurance Co Ltd[1998] EWCA Civ 1853 was a decision of the Court of Appeal relating to the recovery of a payment made by a bank on the mistaken belief that the customer had sufficient cleared funds in the account.
