(1) Where, by virtue of or in consequence of the exercise of, or the failure to exercise, or the release of, a general power of appointment by any person having such a power, a person becomes beneficially entitled in possession to any benefit, then, for the purposes of this Act, the disposition is the exercise of, or the failure to exercise, or the release of, the power and not the disposition under which the power was created, and the person exercising, or failing to exercise, or releasing, the power is the disponer.

(1A) In subsections (1B) and (1C) 'arrangement' includes any agreement, understanding, scheme, transaction or series of transactions (whether or not legally enforceable).

(1B) Notwithstanding subsection (1), where the exercise of, failure to exercise, or release of, a general power of appointment form part of an arrangement the main purpose or one of the main purposes of which is the avoidance of tax, tax shall be chargeable as if the disposition were the disposition under which the power was created and the person who created the power were the disponer.