This Q&A assumes that: • an English court would recognise the English Wills of A and B as mutual Wills on their terms, and • the first testator A was domiciled in England at the time of their death We have not been able to find any authorities which would definitively answer the question. However, we would make the following observations: The main issues which need to be considered appear to be: • would an English Court recognise the formal validity of the surviving testator B’s French Will? • does the constructive trust which arises under B’s English Will as a result of the mutual Will doctrine apply to B’s UK and French assets, or only to their UK assets? In relation to the first issue, in the UK, the Convention of 5 October 1961 on the Conflicts of Laws Relating to the Form of Testamentary