There is an established legal principle that where people have wills benefiting each other (as is normal with the wills of a husband and wife) and the order in which they died cannot be ascertained, it is considered that the older of the two will have been the first to die.
It is also normal for a will to provide a 'survivorship period', so that if the second death closely follows the first, the terms of the will are varied. This can prevent tax and other complications which may arise through the administration of two related estates in rapid succession.
A recent case concerning an elderly couple who died dealt with the very unusual circumstance in which both of the above were in point. The dates of their deaths could not be determined and, in particular, it could not be ascertained which of them had died first. Their wills, which largely gave their estates to one another, both contained a 28-day survivorship clause.
Under the law, the husband, who was the younger of the two, was considered to have survived his wife, but could he be considered to have survived her by 28 days?
The court ruled that he could not, so her gift to him in her will did not take effect. However, the other bequests in their wills did take effect. Since the wills were virtually identical, this led to the unintended consequence that the beneficiaries under them benefited twice, despite this not being what the couple had intended when their wills were drafted.
In giving his decision, the judge indicated that, had the argument been that the will was misdrafted due to a clerical error, that would most likely have been successful and the will rectified. It remains to be seen if an appeal is made to advance that argument.