In the case of Re R (Deceased)  EWHC 936, a claim was brought under the Inheritance (Provision for Family and Dependants) 1975 Act (“the Act”) for reasonable financial provision...
It is possible for two people to leave Wills where, on the first death, the survivor is not free to unilaterally alter their Will and make a new one inconsistent with the mutual Will. If that person does so, their representatives would hold that estate on Trust to perform the equitable obligations arising from the adopted mutual Will.
For that reason, most legal practitioners will advise against making mutual Wills. There are usually better alternatives available to achieve the objectives of the parties involved without tying their hands in relation to Will drafting. Indeed, it used to be the case that practitioners would insert a clause saying that the Will was intended to be mutual if they were unable to persuade a client against it. Nowadays, it is more common to see a clause that says that the Will is not intended to be mutual.
More information on mutual Wills is available in our blog on the subject.