A settlor's carefully drafted timing and conditions count for nothing once the beneficiaries unite against them. This chapter explains the rule itself and who may invoke it, then the three core conditions — including what it means to be collectively absolutely entitled and why the court cannot override a competent adult who refuses to consent. It works through the distinctions that determine whether the rule is available: vested against contingent interests, and severable shares against non-severable ones such as a life tenancy. It closes with the rule's effect once validly invoked — the trustees' duty to comply and the remedy if they do not — and the situations, such as classes including unborn or unascertained persons, where the rule fails and statutory routes take over.
