Probate and Will, Trust & Estate Disputes

Publish date

14 February 2024

How to prevent and combat challenges to wills in a blended family

What is the issue?

In 2021 it was estimated that one third of UK families were ‘blended’, meaning the family contains a combination of parents, new partners and / or children from the old and new relationships.

What does it mean?

Given this accounts for over 6 million families it is crucial that the legal consequences of the increasingly common modern family are carefully considered.

What are the take aways?

This article will explore some recent cases involving blended families, outline the estate planning solutions that can help ensure that the needs of everyone involved are catered for, and highlight the steps that can be taken if a will is challenged or a client wishes to challenge a will.

Preventing challenges to wills: Points to consider when taking instructions from blended families

Most clients would like their wills to be simple, usually leaving assets outright to their partner in the first instance with children / other chosen beneficiaries benefitting following the survivor’s death; but this simplicity can have unintended consequences when the testator is in a blended family.

Practitioners need to be aware of potential issues and discuss solutions with their clients, such as using an Immediate Post Death Interest (IPDI) for a surviving spouse following the first death.  Using an IPDI means that the surviving spouse is protected (for example by being able to continue living in the family home), but that the assets are preserved for the testator’s intended beneficiaries after that. A discretionary trust, coupled with a letter of wishes, could provide flexibility, but the Inheritance Tax (IHT) implications would need to be carefully considered.  In blended families, where there might be a tension between different branches of the family in future (even if there isn’t now), encourage the testator to think about the identity of the executors / trustees:  an independent trustee could be less influenced by family pressures.

Severance of joint tenancies

Wills only cover those assets that pass under them so review the ownership of all joint assets, severing joint tenancies where appropriate.

Assets that do not pass under the will

Pensions and life insurance policies usually don’t pass under the testator’s will, but the testator should take them into account when deciding what to include in their will.  Practitioners should discuss these assets with the testator, to ensure that the testator understands where the devolution of those assets is subject to the discretion of third parties, for example pension trustees.

Any letter of wishes accompanying the testator’s will should refer to these assets to explain why the will has been prepared in the way it has.

Inheritance tax for unmarried couples

Asset protection considerations should not overlook IHT planning.  For unmarried couples, the lack of spouse exemption from IHT means that an IPDI could lead to IHT being paid twice: on the first death and then on aggregation in the estate of the surviving partner.

A fully discretionary trust of residue could avoid this potential double charge, although ongoing charges under the relevant property regime will need to be managed, and consider the loss of the residential nil rate band (as any qualifying residential interest owned by the first to die will not be ‘closely inherited’ where property is left to a discretionary trust).

Section 144 Inheritance Tax Act 1984 can be used within two years of the first death to ‘reorganise’ the estate of the first to die so as to produce a structure which is both as IHT and asset protection efficient as possible. It is crucial that action is taken soon after the first death.  The testator’s wishes should also be set out in a detailed letter of wishes to the will and again, an independent or professional executor / trustee may be appropriate

Who are the beneficiaries?

Practitioners must consider carefully who is included in a class of beneficiaries in a will.  The cases of Reading v Reading [2015] and Marley v Rawlings [2014] confirm that words are interpreted looking at  the ordinary meaning of a word, the context of the will, common sense and facts known or assumed by the testator when the will was prepared. Practitioners can avoid the issue arising by being precise.  For example, rather than referring simply to ‘grandchildren’ take instructions as to whether this should include step-grandchildren, and set it out clearly in the will.

Beneficiaries may be transgender, non-binary or conceived through medically assisted means / surrogacy.  Again, consider the definitions and wording used in the will to ensure the testator’s wishes are clear, even where this is not currently an issue.

Combating claims by step-children/children of the first marriage

Children and step-children are entitled to challenge their parent’s/step-parent’s will on various grounds. In our experience the most commonly alleged grounds are lack of testamentary capacity, lack of knowledge and approval of the contents of the will and undue influence by a third party (typically allegations against second spouses of the deceased). Estates passing on intestacy can also be challenged, often on the basis that the deceased executed a will that provided for the children/stepchildren of the deceased, which has not been proved.

Inheritance (Provision for Family and Dependants) Act 1975 (the 1975 Act)

Section 1(1)(c) of the 1975 Act allows children (whether adults or minors) to claim for reasonable financial provision for their maintenance from a parent’s estate. Stepchildren are entitled to claim this if they can establish standing under section 1(1)(d) of the 1975 Act (broadly where they have been treated as a child of the deceased). This includes adult step-children, stepchildren who have not lived with the deceased and step children who have never been maintained by the deceased.

In Higgins v Morgan [2021], the stepson, Barrie, claimed against his step-father’s estate which passed on intestacy to the deceased’s distant cousins. Stepchildren are not entitled to a share of an estate under the intestacy rules. Barrie was in a poor financial position and made a claim for reasonable financial provision on the basis that the deceased had acted in the role of parent, that he was treated ‘as a child of the family’, that the deceased was financially providing for Barrie at the time of his death which resulted in a ‘moral obligation’, and also demonstrated a need for maintenance.  The Court made an award to Barrie.

Mutual wills

Mutual wills arise where there is an irrevocable agreement between two parties (commonly spouses) that they will not change or revoke their identical wills after the first death.  Where the survivor subsequently changes their will, their executors will hold the estate on the terms of the previous mutual will.  Mutual wills are different to parties signing identical (or mirror) wills, where there is no such binding agreement.

In McLean v McLean [2023] a husband and wife executed mirror wills in 2017 which left their respective estates to each other on the first death. On the second death the estate was to be split equally four ways between the husband’s three children and the wife’s child.  The wife survived her husband, and in 2019 changed her will to benefit only her child, excluding her husband’s three children.  The husband’s children argued that the 2017 wills were mutual wills so the wife was not entitled to change her will.  The court found that whilst the spouses had the common intention to provide for all the children, the issue of mutual wills was not discussed and there was no evidence of a ‘legally binding agreement’ not to change their wills.  As such, the wife’s 2019 will was valid, and the husband’s children received nothing.

Mutual wills are rare and unpredictable:  if a testator wishes to use a mutual will to provide for their ‘blended family’ this should be reflected in the drafting, and you must advise on the consequences of the agreement.  For many reasons though, it is far preferable not to rely on this somewhat uncertain doctrine and to incorporate appropriate drafting to cover all eventualities as discussed above.

Proprietary estoppel

Proprietary estoppel claims involve the enforcement of a promise made to the claimant in respect of property or land that is later reneged on, usually that the claimant will inherit the asset.  Where the claimant relied on this promise to their detriment (for example working for low wages in a family business, after a promise that they would inherit the business), they can bring a claim for proprietary estoppel.

The level of relief for proprietary estoppel was considered in Guest v Guest [2022] which held that the appropriate remedy is to give effect to the claimant’s expectation, rather than to compensate for the detriment suffered. The promisor is held to their promise even if the transfer of the property/land is disproportionate to the financial detriment suffered by the claimant.

Whilst any promises are usually only verbal, if you are aware that your client is relying on such a promise, you should advise them to obtain confirmation in writing from the promisor, and make a careful contemporaneous note of the facts to try to avoid the cost and uncertainty of a future proprietary estoppel claim.


Blended families give rise to many complex issues, but planning in advance can reduce the risk of a testator’s wishes not being followed, or facing a challenge.  Discuss all eventualities, even if they don’t currently seem relevant, and reflect the instructions clearly in the will.  If, despite this, a challenge is brought, be prepared for your file to be examined as part of any proceedings so keep careful records of your discussions and instructions.

This article first appeared in STEP Journal, Issue 1, 2024

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