‘A fruitful parent of injustice is the tyranny of concepts’ (Cardozo 1928). This warning seems apposite when reviewing the impact of the decision of the House of Lords in Hammersmith and Fulham London Borough Council v Monk [1992] 1 AC 478, HL. Since Monk the law is well settled that one joint tenant of a periodic lease can destroy the lease held by both joint tenants. This destructive ability is justified by a conceptual analysis that refuses to recognise the destructive effects of its utilisation. With a reform of the law on the horizon the time is ripe for a review of this peculiar area of law (see Law Com No 284). If we are correct in our analysis, Monk has been productive of an unnecessary amount of mischief in the law. This is partially due to the deployment of inappropriate concepts in Monk itself, and partially due to an unfortunate subsequent tendency to allow these concepts to act as tyrants in dictating legal development. Monk has had an effect directly or indirectly across many different areas of the legal landscape. This has necessitated both an unwelcome length and a complex structure for this article
