Common Law Principles: The foundational principles of unjust enrichment derived from case law, including leading cases such as Lipkin Gorman v Karpnale Ltd [1991] and Investment Trust Companies v Revenue and Customs Commissioners [2017]. These establish the basic requirements for unjust enrichment claims.

Elements of Unjust Enrichment: The four essential elements that must be proven: enrichment of the defendant, enrichment at claimant's expense, the unjust nature of the enrichment, and absence of applicable defenses.

Limitation Act 1980: Establishes the 6-year limitation period for actions founded on simple contract (Section 5) and sets time limits for bringing claims in unjust enrichment cases.

Law of Property (Miscellaneous Provisions) Act 1989: Legislation governing property-related aspects of unjust enrichment claims, particularly relevant when the enrichment involves property transfers or interests.

Civil Procedure Rules: Procedural requirements including pre-action protocols and formal demand requirements that must be followed before initiating court proceedings.

Consumer Rights Act 2015: Relevant legislation when the unjust enrichment claim involves consumer transactions or consumer protection issues.

Financial Services and Markets Act 2000: Applicable legislation when the unjust enrichment claim involves financial services or regulated financial activities.