Mutual wills

The doctrine of mutual wills applies where two testators write their wills under an agreement that both will remain unaltered until the last of them dies.

If the wills are mutual wills any attempt by the survivor to alter his or her will after the death of the first in breach of the agreement will be ineffective and the new beneficiaries will hold the estate on trust for the original beneficiaries.

While this commonly involves ‘mirror’ wills (where for example two spouses execute wills leaving everything to the surviving spouse or if they have already died to their children) the mere existence of mirror wills does not necessarily mean that they are mutual wills.

The testatrices M and E were sisters. In 1991 they made mirror wills leaving everything to each other and after that to be...