Focuses on the distinct doctrines of constructive trusts and proprietary estoppel which are as most recent cases suggest now being assimilated. A constructive trust or proprietary estoppel is a claim by one party to, or to an interest in, property owned by another. Invariably the property concerned is land for which there are formal requirements to be satisfied if there is to be a legally binding contract to effect the transfer. Under these doctrines the court has power to make an order in favour of a claimant on some promise or representation by the property owner. Looks at the implications of the court's treatment of such claims in relation to disposal for Capital Gains Tax purposes or transfer of value for Inheritance Tax. Examines several recent cases illustrative of the issues involved including "Hyett v Stanley"([2003] EWCA Civ 947, 67103) and "Van Laethem v Brooker"([2005] EWHC 1478 (Ch)).