"If the interest to be assigned is a creature of equity, such as the beneficial interest of a cestui que trust, then, apart from any statutory provisions, an assignment of it can, of course, only be effected in equity; for the common law does not know it. Any present assignment of such an interest, that is to say of a chose in equity, is therefore necessarily an equitable assignment. Such an assignment can be by way of gift; and, except that writing is required by s 9 of the Statute of Frauds, no formality is necessary beyond a clear expression of an intention to make an immediate disposition. In short, there is no reason at all why a person should not give away any beneficial interest that is his: the classic statement is that of Knight Bruce LJ in Kekewich v Manning [1851] EngR 997; (1851) 1 De G M & G 176 (42 ER 519); see too In re McArdle (dec'd) [1951] 1 Ch 669. It is, of course, necessary that the transaction should take the form of, and be intended as, an immediate transfer of the beneficial interest of the assignor, as distinct from an agreement to assign it. The distinction is critical, for consideration is always necessary to attract the support of equity to a transaction that is a contract rather than a conveyance. The judgment of Stuart VC in Voyle v Hughes [1854] EngR 88; (1854) 2 Sm & G 18 (65 ER 283), puts all this clearly (at p31)."