Trust and estate disputes viewed through the lens of Knives Out!

Brooke Clarke, Trainee in the Russell-Cooke Solicitors, charity law and not for profit team.
Brooke Clark
4 min Read

The coinciding of two unrelated events – the start of my seat in the trust and estate disputes team, and the release of Glass Onion: A Knives Out Mystery – has had me rethinking the plot of 2019 hit Knives Out through a new lens… albeit one which is framed by the law of England and Wales.

In the 2019 film, we see a family on the cusp of all-out legal war over their inheritance, following the suspicious suicide (or, more likely, murder) of the family’s wealthy patriarch, Harlan Thrombey. Enter Marta: nurse to the late head of the household and sole beneficiary under his will. In the format of a classic whodunit, Knives Out navigates the family’s journey to determine who is culpable for Harlan’s death.

It is important to note that this film is set in the United States but for our purposes, let's imagine that the events of the film took place in England, and that the patriarch was domiciled here too. (This is crucial as the following analysis differs across jurisdictions.)

Over two hours and ten minutes of final run-time, Marta faces the wrath of the Thrombey family: some attempt to convince her to renounce the inheritance completely, whereas others try to manipulate her into giving them a cut of the estate. So – what legal claim does this eclectic mix of characters have over Marta?


Most of the key players in Knives Out could have been responsible for Harlan’s murder – if indeed he was murdered – including Marta. As the sole beneficiary under his will, had Marta been found to have unlawfully killed Harlan, this would preclude her from acquiring a benefit in consequence of the killing: namely, her inheritance. In the film, this avenue for investigation is led by the ever-present detective Benoit Blanc, whose purpose throughout Knives Out is to identify Harlan’s killer.

Contesting the will

Should it have been found by Detective Blanc that there was no foul play involved in Harlan’s passing, thereby shutting off the possibility of forfeiture from the Thrombey family, another approach would be to contest the will.

Under the law in England and Wales, there are five underlying grounds that can be used to challenge the will. These are:

  • lack of testamentary capacity
  • undue influence
  • testator’s lack of knowledge and approval
  • where the formalities of the Wills Act 1837 have not been fulfilled
  • presence of forgery or fraud

In fact, the presence of suspected undue influence was put forward by the Thrombey family as a possible reason for Marta being named the sole beneficiary of the will. Given that Marta cared for the patriarch in his final days in her capacity as his caregiver, it may have been the case that Harlan (a vulnerable individual) was influenced to make a will benefitting Marta against his own volition.

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

Under the 1975 Act, certain categories of persons have the standing to bring a claim against the estate of a deceased person where ‘reasonable financial provision’ has not been made under the terms of the will (or on the intestacy of the deceased). For Knives Out, this means that Harlan’s children, or indeed any individual he wholly or partly maintained, may make an application for provision under the Act. And given the horror expressed by his children when confronted with the possibility of having to find another means to fund their lavish lifestyles, we would be forgiven for assuming that this piece of law might apply!


Knives Out ends with Marta, both inheritance and a mug of tea in hand, standing on the balcony of her newly-acquired mansion as the remainder of the family squabble below. As it happens, none of the above law is applied, nor do the Thrombeys seem to take an adequate legal route to securing financial provisions for their future. Although – this may all change with the release of Glass Onion and the subsequent events it details.

But this story, whilst entirely fictional, demonstrates just one scenario within which an inherited wealth dispute might arise. Multi-jurisdictional families and estates, blended family structures and evolving family dynamics and succession issues are just some of the circumstances that add scope for dispute.

It’s clear from my time within the trust and estate disputes team at Russell-Cooke that, just like the titular Glass Onion, there are many fragile layers which make up our work on trust and probate disputes.

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