The scope of the ultra vires doctrine

In the context of succession law, an act or transaction of the praepositus which offends against the interests of the legal heirs established by the laws of inheritance may properly be termed ultra vires since it exceeds the permitted limits of the discretionary transmission of property at death. The interests of the legal heirs become, of course, fully mature at the time of the praepositus' death, so that any testamentary disposition of property, becoming effective only after the testator's death, is potentially ultra vires. But the law goes further and regards the rights of the legal heirs as crystallising at the moment when it can be established that the process of the praepositus' dying had irrevocably begun. Accordingly, acts of the praepositus performed during what is termed his death-sickness may be caught by the ultra vires doctrine insofar as they are deemed to constitute an infringement of the interests of the legal heirs. Two concluding chapters will consider both these limbs of the ultra vires doctrine in some detail.

The one-third rule

Bequests which, singly or collectively, exceed in value one-third of the testator's net estate – i.e. the assets available for distribution after the payment of funeral expenses and debts – are ultra vires to the extent of the excess portion.

The time for calculation of the bequeathable third

As thus stated, the rule is common to all the schools of law.