What is the test for invoking the presumption of undue influence?

37 In the case of a gift of sufficient magnitude so as not to be accounted for by "ordinary motives on which ordinary men act", all that need be shown by the plaintiff to raise the presumption is some "special relationship". Courts have found the existence of a fiduciary relationship, or something less such as a confidential or advisory or guiding relationship, to be sufficiently influential to raise the presumption (Geffen v. Goodman, supra, pp. 221-222). Wilson J. in Geffen v. Goodman suggested that a preferable way of describing the requisite relationship is where one person has the ability to dominate the will, i.e. exercise a persuasive influence over another, whether through manipulation, coercion or outright but subtle abuse of power. She set out the test for invoking the presumption at p. 227: "What then must a plaintiff establish in order to trigger a presumption of undue influence? In my view, the inquiry should begin with an examination of the relationship between the parties. The first question to be addressed in all cases is whether the potential for domination inheres in the nature of the relationship itself. This test embraces those relationships which equity has already recognized as giving rise to the presumption, such as solicitor and client, parent and child, and guardian and ward, as well as other relationships of dependency which defy easy categorization."