For a trust to be valid, it requires the coincidence of three conditions which are known as "the three certainties". If any of these conditions are absent then the trust will be void ab initio, form the very start. The proposition of the three certainties is taken from the dictum of Lord Langdale in the leading case Knight v Knight 1 :
"As a general rule, it has been laid down, that when property is given absolutely to any person, and the same person is, by the giver who has power to command, recommend, or entreated or wished, to dispose of that property in favour of another, the recommendation, entreaty or wish shall be held to create a trust. First if the words were so used, that upon the whole, they ought to be construed as an imperative; secondly, if the subject of the recommendation or wish is certain; and thirdly, if the objects or persons intended to have benefit of the recommendation or wish also be certain."
