An agreement for mutual wills must be proved on the balance of probabilities, but the nature of the allegation — that deceased persons bound themselves not to revoke their wills — requires clear and satisfactory evidence, consistent with the [name withheld] principle. The making of identical wills on the same day, even by the same solicitor, is insufficient to establish such an agreement. The doctrine of mutual wills is not confined to cases where the surviving testator benefits under the will of the first to die; the equitable fraud lies in the betrayal of the agreement, not in the receipt of a benefit.
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