Estate Duty surviving spouse exemption: powers where the person is not competent to dispose
A person who has a power, whether of appointment or of revocation and resettlement, that can be exercised only with the consent of, or jointly with, others is not regarded as competent to dispose, (IHTM04457) even if they are an object of the power, or if the power is treated in law for other purposes as a general one (Commissioner of Estate and Succession Duties (Barbados) v Bowring  AC 171)
A person who has a general power of appointment by will only and who, in their lifetime, releases that power is not regarded as having been competent to dispose of the settled property. Any will executed before the release of the power could not have conferred any benefit, during the testator’s lifetime, on the appointee.
Whether the power can be exercised by will or by deed, (IHTM04460) or both will have a bearing on the competency to dispose.
If a surviving spouse is both life tenant and entitled to an absolute interest in the settled property expectant on the death of a second and surviving limited owner, the ownership of the reversionary interest does not make them competent to dispose.