Late Payment of Commercial Debts (Interest) Act 1998: Governs statutory interest rates and compensation for late payment in commercial transactions. Key consideration for calculating interest claims in demand letters.

Limitation Act 1980: Sets time limits for bringing claims. Ensures the debt isn't statute-barred (6-year limitation period for simple contracts). Must be checked before issuing demand letter.

Consumer Credit Act 1974: Provides consumer protection provisions and regulatory requirements when dealing with consumer debt. Affects format and content of demand letters for consumer debts.

Practice Direction - Pre-Action Conduct and Protocols: Sets out requirements for reasonable steps before court proceedings, including specific content and timing requirements for demand letters.

Pre-Action Protocol for Debt Claims: Details specific requirements for debt collection and mandatory information that must be provided to debtors in demand letters.

Contract Law Principles: Fundamental principles regarding terms of original agreement and elements of breach of contract that must be referenced in demand letter.

Consumer Rights Act 2015: Contains fairness requirements and consumer protection provisions that must be considered when drafting demands to consumers.

GDPR and Data Protection Act 2018: Governs handling of personal information and privacy considerations in correspondence. Must be complied with when drafting and sending demand letters.