Court finds wills to be mutual despite a contrary wording in them. Judge states mutual wills may not require a contract and that they could be based on proprietary 'estoppel'. Estoppel applies in English law whereby a court may prevent, or "estop", a person from going back on a promise they have made.
In this case, both husband and wife had promised, with mutual 'mirror' wills, that the daughters would inherit all on 2nd death and subsequently, after the husband passed away leaving everything to his wife, she then changed her will several times to only leave the daughters a minor interest and most of the estate to pass to grandchildren and other beneficiaries.
The Judge overruled the most recent wills with the estate was awarded in entirety to the daughters saying that a mutual agreement, despite being verbal, had been agreed and was therefore a binding contract that the daughters should inherit all of the estate.
Credit to IFA technical service www.techlink.co.uk for case notes on Legg and Others v Burton and Others  EWHC 2088 (Ch).