(1) Where, by an agreement made in relation to any future copyright and signed by or on behalf of the prospective owner of the copyright, the prospective owner purports to assign the future copyright (wholly or partially) to another person (in this subsection referred to as “the assignee”), then if, on the coming into existence of the copyright, the assignee or a person claiming under him or her would be entitled as against all other persons to require the copyright to be vested in him or her (wholly or partly, as the case may be), the copyright shall, on coming into existence, vest in the assignee or his or her successor in title by virtue of this subsection.