Primarily, the mirror will is an administrative convenience. Mirror wills is almost self-descriptive term. These wills are but not exclusively written by two people in some manner of romantic relationship. The legal status of the relationship – civil partnership, cohabitation or marriage is immaterial. A romantic relationship between the testators is a common feature, but not a prerequisite for such a will. However, there is nothing preventing people in any other sort of relationship from entering into a mirror will.
As one of the principal aims of a will is to dispose of the estate of the testator, the parties to mirror wills would have some property or children in common. They, usually in my experience own a house jointly.
Brenda and Simon live together. They own a house jointly and have a couple of children. Their wills are similar, Brenda’s will refers to ‘my partner Simon’, and ‘my partner’s sister Jane’. Simon’s will mentions ‘my partner Brenda’ and ‘my partner’s sister Amber’. These points could be fundamental to the execution of the wills, nonetheless, as these are the only differences between the two documents, by corollary, all other elements are identical, these are mirror wills. Each document is more a less a reflection of the other.
There is nothing in the law, practice or convention preventing one or other party from changing the provisions of his or her will at any time. One testator may alter the will without the consent of the other – at any time – before or after the death of the other party.
The inheritance tax treatment of gifts between spouses and civil partners, (the transferable nil rate band and the residential nil rate band) differ from gifts between parties in all other relationships, therefore, any inheritance tax planning would need to reflect the relationship between the testator on the one hand and the beneficiaries on the other.
Mirror wills should not be confused with joint wills or a mutual will. These are to be avoided as they would land the estate, testators, and draughtsman in no end of trouble.