The essence f a trust is that it is an obligation concerning property which is enforceable in the courts which will control the trustees and, in rare cases, even carry out the trust. There must thus be beneficiaries who can apply to the court to enforce their rights. It follows that a trust must be created for the benefit f persons but not for a purpose unless that purpose is charitable, for a purpose can not sue, but if it be charitable the Attorney General may sue to enforce it. It is therefore the beneficiary principle which will often be the deciding factor in whether a case is successful as a purpose trust or not.
The leading case for the theory is that f Morice v. Bishop f Durham . The testatrix in this case had bequeathed all her property to the Bishop f Durham upon trust for 'such objects f benevolence and liberality as the Bishop f Durham in his own discretion shall most approve of.' It was held that the trust was not charitable and could not stand as a private trust either because it had no specific beneficiaries and had been made purely for a purpose. 'Every other trust must have a definite object. There must be somebody in whose favour the Court can decree performance.' Sir William Grant MR.
Administrative workability is also essential in that there is a certainty f who the trust is to benefit. Lord Eldon said this in Morice v Bishop f Durham: "As it is a maxim that the execution f a trust shall be under the control f the court it must be f such a nature that it can be under that control; so that the administration f it can be reviewed by the court, or the court itself can execute the trust: a trust, therefore, which in case f maladministration could be reformed and a due administration directed." It then follows that the trust must not be impossible to perform. A time limit as to the life span f the trust is also often necessary so as not to have it go on forever because it may not be in the public interest. Finally, if the purpose f the trust is capricious, useless, wasteful, harmful, illegal or otherwise contrary to public policy, it will obviously fail.
There are a number f exceptions to the invalidity f purpose trusts, however it is the general dislike f these trusts that have lead to them being recognised as 'troublesome, anomalous and aberrant' .: Re Endacott  presented a gift to the parish council for "the purpose f providing some useful memorial to myself". Harman LJ at first instance refused to uphold such a trust and said 'these cases stand by themselves and ought not to be increased in number, nor indeed followed, except where one is exactly like another'. However, it was eventually held to be valid on the reasoning that it asses to and improved the fabric f the church.
A further exceptional case was that f Re Hooper  in which it was held to be a valid purpose trust because it had been limited in perpetuity. Most instances f cases, known as the 'monument' cases, are found to be subject to rules f perpetuity and will therefore be valid. Trusts for the saying f masses are often also valid because there is a close religious link; Re Hetherington  . Trusts for the maintenance f particular animals (such as in the case f Re Dean (1889)) may also be held valid because there is the ability to establish certainty f object, being the animals.
It is a general rule that the law does not recognise non-charitable purpose trusts and they are