Purpose Trusts (Equity and Trust Law)

Order Description
�The objection [to purpose trusts] is that there cannot be an obligation upon the trustees unless there is a correlative right in someone else to enforce it.� Hanbury &
Martin; Nineteenth Edition, page 396.
To what extent do the courts sustain this objection when ruling on the validity of purpose trusts. Is this objection a useful one? Discuss with reference to relevant
case law.