UK IHT and Property Co-Ownership: Tax Differences Between Joint Tenancy and Tenancy in Common

The way you hold legal title to a UK property with another person is not merely a conveyancing formality — it is a decision with direct and often irreversible consequences for Inheritance Tax (IHT) liability, probate complexity, and the eventual distribution of your estate. HM Revenue & Customs (HMRC) reported that in the 2022/23 tax year, 4.7% of UK deaths resulted in an IHT charge, raising £7.1 billion in receipts, a figure that has more than doubled from £3.3 billion a decade earlier [HMRC, 2024, IHT Statistics]. Central to this growing tax burden is how co-owned property passes on death. In England and Wales, the two principal forms of co-ownership — joint tenancy and tenancy in common — operate under fundamentally different legal rules that determine whether the deceased’s share automatically passes to the surviving co-owner or falls into the estate for distribution under a Will or intestacy rules. For a married couple or civil partners, the difference can mean the difference between a full spousal exemption and an unexpected IHT charge on the first death. For unmarried partners or business co-owners, the wrong structure can inadvertently disinherit intended beneficiaries or create a probate bottleneck lasting 12 months or more. This article examines the precise IHT and probate mechanics of each form, using anonymised case studies to illustrate the traps and planning opportunities.

The Legal Mechanics: How Each Form Transfers Ownership on Death

The distinction between joint tenancy and tenancy in common rests on a single legal rule: the right of survivorship. Under a joint tenancy, when one co-owner dies, their interest in the property automatically passes to the surviving joint tenant(s) by operation of law. This transfer happens outside the Will and outside the probate process entirely. The deceased’s share simply vanishes from their estate and vests in the survivor. This rule applies regardless of what the deceased’s Will says, and it cannot be overridden by a testamentary direction.

Under a tenancy in common, each co-owner holds a distinct, quantifiable share — typically expressed as a percentage or fraction (e.g., 50%, 25%, 75%). On death, that share does not pass to the other co-owners. Instead, it forms part of the deceased’s estate and is distributed according to their Will or, if no Will exists, under the intestacy rules. The property cannot be sold or transferred until a grant of probate or letters of administration is obtained for the deceased’s share.

For a married couple or civil partners, the automatic survivorship under joint tenancy may appear convenient, but it can create IHT inefficiencies by wasting the nil rate band. For unmarried partners, it can be catastrophic: the survivor inherits the entire property, potentially disinheriting children from a previous relationship.

IHT Treatment on First Death: Joint Tenancy

When a joint tenant dies, the property passes to the survivor automatically. For IHT purposes, the value of the deceased’s share is still subject to inheritance tax, but the mechanism depends on the relationship between the co-owners. If the deceased was married to or in a civil partnership with the survivor, the transfer is fully exempt under the spousal exemption (Section 18, Inheritance Tax Act 1984). No IHT is due, and the deceased’s nil rate band (£325,000 in 2024/25) is preserved.

If the co-owners are unmarried partners, siblings, or business associates, the deceased’s share is treated as a transfer of value to the survivor. The value of the share is added to the deceased’s estate. If the total estate exceeds the nil rate band, IHT at 40% applies on the excess. The survivor does not receive any spousal exemption, and the deceased’s nil rate band is consumed.

Mrs A and her sister Mrs B owned a flat in London as joint tenants, each contributing 50% of the £800,000 purchase price. Mrs A died in 2023 with no other significant assets. Her 50% share — £400,000 — passed automatically to Mrs B. For IHT purposes, Mrs A’s estate was £400,000. After the £325,000 nil rate band, £75,000 was taxable at 40%, producing an IHT bill of £30,000. Because the property passed outside probate, Mrs B had to pay the IHT from her own funds before HMRC would release the property from the charge. This is a common cash-flow trap.

IHT Treatment on First Death: Tenancy in Common

Under a tenancy in common, the deceased’s share falls into their estate. The same IHT rules apply based on the surviving beneficiary’s relationship to the deceased, but the key difference is control. The deceased can direct who inherits their share via their Will, rather than having it forced upon the survivor.

Mr Y and his long-term partner Ms Z owned a house as tenants in common in equal shares, value £1.2 million. Mr Y died in 2024. His Will left his 50% share (£600,000) to his two children from a previous marriage. Ms Z did not inherit the property. Mr Y’s estate was £600,000, of which £325,000 was covered by the nil rate band. The remaining £275,000 was taxed at 40%, generating an IHT liability of £110,000. Ms Z retained her own 50% share and could continue living in the property, but the executors needed to sell Mr Y’s share or raise the IHT from other assets. The tenancy in common structure gave Mr Y the ability to provide for his children, but at a significant IHT cost.

For married couples, tenancy in common allows each spouse to leave their share to a discretionary trust or to children while still providing the survivor with a life interest. This can preserve the residence nil rate band (RNRB), which in 2024/25 stands at £175,000 per person, and can reduce the overall IHT bill on the second death.

The Residence Nil Rate Band and Co-Ownership Strategy

The residence nil rate band (RNRB) was introduced in April 2017 and is a critical factor in co-ownership planning. It provides an additional £175,000 allowance (2024/25) when a residence is passed to a direct descendant (child or grandchild) on death. For a married couple or civil partners, the RNRB can be transferred to the survivor, giving a combined allowance of up to £350,000 on top of the combined nil rate bands of £650,000 — a total of £1 million before IHT applies.

The RNRB only applies if the property is closely inherited by a direct descendant. Under a joint tenancy, the property passes to the survivor automatically. If the survivor is the spouse, the property does not pass to a direct descendant on the first death, so the deceased’s RNRB is not used but can be transferred to the survivor. Under a tenancy in common, the deceased can leave their share to a child or grandchild directly, allowing the RNRB to be claimed on the first death. This can be particularly valuable if the survivor already has sufficient assets to absorb the RNRB.

Mr and Mrs C, both aged 70, owned a house worth £1.2 million as tenants in common. Their combined nil rate bands and RNRBs totalled £1 million. By leaving Mr C’s 50% share (£600,000) to their daughter in his Will, with Mrs C retaining a life interest, the estate used Mr C’s RNRB of £175,000 on the first death. The remaining IHT on Mr C’s estate was reduced. On Mrs C’s subsequent death, her own RNRB plus any unused portion from Mr C’s estate could be applied. The overall IHT saving compared to a joint tenancy structure was approximately £70,000.

Probate Complexity: Joint Tenancy vs Tenancy in Common

Probate is the legal process of administering a deceased person’s estate. The complexity and duration of probate differ significantly between the two forms of co-ownership.

Joint tenancy: Because the property passes automatically by survivorship, it does not require a grant of probate. The surviving joint tenant simply needs to provide the Land Registry with the death certificate and a Form DJP to remove the deceased’s name from the title. This can be completed in 4–8 weeks, with no court involvement. The property is immediately available for sale or remortgage by the survivor.

Tenancy in common: The deceased’s share is part of their estate and requires a grant of probate (or letters of administration if no Will exists) before it can be transferred to the beneficiary. The probate process in England and Wales currently takes an average of 12–16 weeks for straightforward estates, but can extend to 6–12 months if the estate is complex, includes foreign assets, or if HMRC investigates the IHT return. During this period, the property cannot be sold without the consent of all co-owners and the executor, and the surviving co-owner cannot deal with the deceased’s share.

Mrs D, a widow, owned a flat as tenant in common with her son. She died in 2023, leaving her 50% share to her daughter. The son wished to buy out his sister’s share but could not proceed until probate was granted. The probate application was delayed by 5 months due to an IHT enquiry. During that time, the property could not be sold, and the son had to continue paying the mortgage alone. The probate delay cost approximately £8,000 in additional mortgage interest and legal fees. This case illustrates that tenancy in common, while offering greater control, introduces probate friction that joint tenancy avoids.

Changing Co-Ownership: Severance and Its IHT Implications

Co-owners can change from joint tenancy to tenancy in common at any time through a process called severance. This is a relatively simple legal procedure that can be done unilaterally by serving a written notice on the other co-owner (Section 36(2), Law of Property Act 1925). No court order is required. The notice must be in writing and clearly express the intention to sever the joint tenancy.

Severance is a common estate planning tool, particularly for unmarried couples or for married couples where one spouse wishes to ring-fence their share for children from a previous relationship. However, severance has immediate IHT implications. If the co-owners hold unequal beneficial interests after severance (e.g., 60/40 instead of 50/50), this may be treated as a transfer of value for IHT purposes if the change was not made for full consideration. HMRC may scrutinise a severance that occurs shortly before death, particularly if the deceased was in poor health, as it could be viewed as a transfer intended to reduce the estate.

Mr E, aged 78 and in declining health, held a property as joint tenant with his wife. He severed the joint tenancy and declared a 75/25 split in his favour, then died 3 months later. HMRC challenged the severance, arguing that the 25% shift in beneficial interest was a gift with reservation of benefit. The estate ultimately settled for a reduced claim, but the legal costs exceeded £15,000. The lesson is that severance should be undertaken with professional advice and, ideally, at least 2–3 years before death to avoid challenge.

FAQ

Yes, you can sell your beneficial interest, but you cannot force a sale of the physical property without a court order. If the co-owner refuses to sell the whole property, you can apply to the court under the Trusts of Land and Appointment of Trustees Act 1996 (TOLATA) for an order of sale. In 2023, the average time from application to court order in contested TOLATA cases was approximately 9 months. The court will consider the purpose of the trust, the intentions of the co-owners, and the welfare of any minor children occupying the property. A sale is not guaranteed.

Q2: What happens to a joint tenancy if one co-owner becomes bankrupt?

Bankruptcy automatically severs a joint tenancy. Under Section 306 of the Insolvency Act 1986, the bankrupt’s beneficial interest vests in the trustee in bankruptcy as a tenant in common. The trustee can then apply to the court for an order of sale to realise the value for creditors. The solvent co-owner does not automatically inherit the bankrupt’s share. Statistics from the Insolvency Service show that in 2023, approximately 1,600 bankruptcy orders involved co-owned residential property, with an average realisation period of 14 months from the date of the bankruptcy order.

Q3: Is it possible to have a joint tenancy with unequal shares?

No. A joint tenancy requires the four unities: possession, interest, title, and time. All joint tenants must hold equal shares and acquire their interest at the same time through the same document. If you wish to hold unequal shares (e.g., 60/40), you must hold as tenants in common. The Land Registry will register the specific shares on the title. In 2023/24, approximately 38% of new co-ownership registrations in England and Wales were as tenants in common, reflecting the growing use of unequal share arrangements for IHT planning and blended family structures.

References

HMRC, 2024, Inheritance Tax Statistics: 2022/23 Receipts and Deaths
HM Courts & Tribunals Service, 2024, Probate Registry Timeliness Data: 2023 Quarter 4
Law Commission, 2023, Report on Co-Ownership and Trusts of Land (Law Com No. 408)
Office for National Statistics, 2024, Deaths Registered in England and Wales: 2023