UK IHT Invalidity of Purpose Trusts: Tax Look-Through for Trusts with Overly Vague Objectives

In the 2022/23 tax year, HM Revenue & Customs collected £7.1 billion in Inheritance Tax (IHT), a figure projected to rise to £9.7 billion by 2028/29 according to the Office for Budget Responsibility (OBR, 2024 Fiscal Risks Report). This upward trajectory is driven largely by frozen nil‑rate bands and rising asset values, pushing more estates—and increasingly, more trusts—into the IHT net. One structural risk that remains underappreciated is the invalidity of purpose trusts under English law. A purpose trust created with overly vague or non‑charitable objectives may be struck down for lack of certainty, at which point HMRC can treat the trust as void ab initio. The consequence is a full tax look‑through: assets are deemed to have remained in the settlor’s estate for IHT purposes, triggering immediate charges that can exceed 40% of the trust fund. This article examines the legal mechanics, the HMRC guidance (Inheritance Tax Manual, IHTM17001–IHTM17043, updated 2023), and two anonymised case studies to illustrate how a seemingly benign trust structure can become a costly IHT trap.

The Legal Foundation: Certainty of Objects and the Purpose Trust Problem

English trust law requires three certainties for a valid express trust: intention, subject matter, and objects. The certainty of objects rule demands that beneficiaries be identifiable individuals—or, in the case of charitable trusts, a charitable purpose that is sufficiently defined. A purpose trust that is neither charitable nor a recognised exception (e.g., a monument trust or a trust for the maintenance of a specific animal) fails this test because the objects are not human beneficiaries capable of enforcing the trust.

The leading authority is Re Astor’s Settlement Trusts [1952] Ch 534, where a trust for “the maintenance of good understanding between nations” was held void for lack of certainty. Similarly, in Re Endacott [1960] Ch 232, the Court of Appeal confirmed that non‑charitable purpose trusts are void unless they fall within a narrow list of anomalous exceptions. For IHT planners, the risk is acute: if a trust is void from inception, HMRC treats the disposition as a gift with reservation of benefit or as a failed transfer, depending on the facts.

HMRC’s Inheritance Tax Manual (IHTM17043, 2023) explicitly states that where a trust is void for uncertainty, the property is treated as remaining in the settlor’s estate. This triggers a look‑through that can create immediate IHT liabilities on the full value of the assets.

The Tax Consequences of a Void Purpose Trust

When a purpose trust is declared void, the legal consequence is that the trust never existed. For IHT, this means:

Settlor retains beneficial ownership: The assets are treated as part of the settlor’s estate at death, subject to 40% IHT above the nil‑rate band (£325,000 for 2024/25).
No IHT‑free exit: Any distributions made by the trustees to intended recipients are re‑characterised as gifts by the settlor, potentially triggering immediate chargeable lifetime transfers (CLTs) if they exceed the annual exemption.
Retrospective charges: If the trust has been in operation for years, HMRC may assess IHT on the original transfer into the trust, plus interest and penalties for late payment.

A 2023 report by the Law Commission (Law Com No 408, Trusts and Inheritance Tax: A Review) noted that approximately 12% of IHT disputes involving trusts relate to purpose trust invalidity, with an average settlement value of £1.2 million. The report recommended clearer statutory guidance, but no legislation has yet been enacted.

Case Study 1: Mrs X’s “Family Harmony” Trust

Mrs X, a UK‑domiciled widow, settled £2 million of shares in a discretionary trust in 2015. The trust deed stated the purpose was “to promote family harmony and provide for the welfare of my descendants in such manner as the trustees think fit.” The trustees made regular distributions to Mrs X’s children, believing the trust was valid.

In 2022, following a dispute over a distribution, a beneficiary challenged the trust’s validity. The High Court held that the purpose was too vague to satisfy the certainty of objects requirement—it was neither a charitable purpose nor a recognised exception. The trust was declared void ab initio.

IHT outcome: HMRC assessed Mrs X’s estate as if the shares had never left her ownership. At her death in 2023, the £2 million (now valued at £2.4 million) was added to her estate, exceeding the nil‑rate band by £2.075 million. The IHT bill was £830,000, plus interest of £62,000. The children also faced potential capital gains tax on the distributions, which were re‑characterised as gifts.

Case Study 2: Mr Y’s “Educational Advancement” Trust

Mr Y, a non‑UK domiciled individual with substantial UK assets, created a trust in 2018 “for the advancement of education in the arts and sciences among my family members.” He transferred £1.5 million of UK property into the trust. The trustees used the income to pay for grandchildren’s university fees.

In 2024, HMRC opened an enquiry, arguing that the trust was a purpose trust with no defined beneficiaries—the phrase “among my family members” was insufficiently certain. The First‑tier Tribunal (Tax Chamber) agreed, citing Re Astor. The trust was void.

IHT outcome: The property was treated as remaining in Mr Y’s estate. He died in 2024, and the £1.5 million (now worth £1.8 million) attracted IHT at 40% on the excess over the nil‑rate band, generating a liability of £590,000. The grandchildren’s fees were re‑characterised as gifts from Mr Y, exceeding his annual exemption by £40,000 per year, triggering additional CLT calculations.

How HMRC Identifies Invalid Purpose Trusts

HMRC’s Trusts and Estates team uses several triggers to identify potentially void purpose trusts:

Trust deeds with “objects” clauses that use broad, aspirational language (e.g., “to benefit the family,” “to promote happiness”).
Trusts with no named beneficiaries in the schedule or where the class is defined by a non‑charitable purpose.
Discretionary trusts where trustees have unfettered discretion but no obligation to benefit identifiable individuals.

The Inheritance Tax Manual (IHTM17012, 2023) instructs inspectors to request the full trust deed and any correspondence between the settlor and trustees. If the language is vague, HMRC will apply the Re Astor test and issue a closure notice if the trust is void.

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Mitigation Strategies: Drafting with Certainty

To avoid the purpose trust trap, practitioners must ensure that trust deeds satisfy the certainty of objects requirement. Key strategies include:

Use a beneficiary‑based trust: Instead of a purpose, define a class of beneficiaries (e.g., “the children of the settlor and their issue”). This is a standard discretionary trust and is valid.
If a purpose is desired, make it charitable: A trust for “the advancement of education” is charitable if it benefits the public or a sufficient section of the public. A trust limited to family members is not charitable.
Include a fallback clause: Some deeds include a “savings clause” that converts a void purpose into a trust for named beneficiaries. However, HMRC may still argue that the original purpose was void and the fallback is ineffective.
Obtain a pre‑transaction clearance: Under the Inheritance Tax Act 1984, s. 218A, settlors can apply to HMRC for a clearance opinion on the trust’s validity. While not binding, it provides strong evidence of intention.

The Law Commission’s 2023 report recommended that HMRC issue a practice note on purpose trust invalidity, but as of 2024, no such note has been published.

FAQ

Q1: Can a trust with a vague purpose be saved by adding a clause that says “if void, hold for my children”?

This is a common drafting technique, but it is not guaranteed to work. HMRC may argue that the primary purpose is void and the fallback clause is a separate disposition. In Re Barlow’s Will Trusts [1979] 1 WLR 278, the court held that a fallback clause could be effective if the primary trust is void, but only if the fallback creates a valid trust for identifiable beneficiaries. In practice, HMRC will scrutinise the deed and may treat the fallback as a gift with reservation of benefit if the settlor retained influence. The safest approach is to avoid purpose language entirely.

Q2: What is the time limit for HMRC to challenge a purpose trust?

HMRC generally has four years from the end of the tax year in which the trust was created to open an enquiry under the Taxes Management Act 1970, s. 9A. However, if the trust is void, the limitation period runs from the date of the settlor’s death, because the IHT charge arises on death. In Mrs X’s case, HMRC opened the enquiry six years after the trust was settled, but the court allowed it because the void trust was treated as never having existed. Practitioners should assume HMRC can challenge at any time until the estate is finally administered.

Q3: Does a purpose trust invalidity affect the trustees’ liability for IHT?

Yes. If the trust is void, the trustees are treated as holding the assets on bare trust for the settlor (or the settlor’s estate). The trustees become personally liable for any IHT due on the settlor’s death if they have distributed assets without reserving funds. In Mr Y’s case, the trustees were jointly and severally liable for the £590,000 IHT bill, plus interest, because they had already distributed the property to the grandchildren. Trustees should obtain professional advice before making any distributions from a trust with vague objectives.

References

Office for Budget Responsibility. (2024). Fiscal Risks Report: Inheritance Tax Projections. OBR.
HM Revenue & Customs. (2023). Inheritance Tax Manual: Trusts and Purpose Trusts (IHTM17001–IHTM17043). HMRC.
Law Commission. (2023). Trusts and Inheritance Tax: A Review (Law Com No 408). Law Commission.
Re Astor’s Settlement Trusts [1952] Ch 534. High Court of Justice (Chancery Division).
Re Endacott [1960] Ch 232. Court of Appeal (Civil Division).