英国遗产税与房产共有形式：联合共有与按份共有的税务差异

The way you hold the legal title to your UK residential property is not merely a conveyancing formality; it is one of the single most influential factors determining how Inheritance Tax (IHT) will apply when the first co-owner dies. HM Revenue & Customs (HMRC) reported that over £7.1 billion in IHT was collected in the 2023/24 tax year, a 9% increase year-on-year driven largely by frozen nil-rate bands and rising property values [HMRC, 2024, Annual IHT Statistics]. For a married couple or civil partners owning a home worth £500,000, the difference between holding as Joint Tenants (“Beneficial Joint Tenants”) or as Tenants in Common (“Beneficial Tenants in Common”) can alter the surviving owner’s eventual IHT liability by more than £40,000. The core distinction is mechanical but profound: under a Joint Tenancy, the deceased’s share automatically passes to the survivor by survivorship, bypassing the Will entirely; under a Tenancy in Common, the deceased’s fractional share forms part of their estate and follows the terms of their Will. This article examines how each form interacts with the Residence Nil-Rate Band (RNRB), the transferable nil-rate band, and the practical steps you can take today to optimise your estate plan.

The Legal Mechanics: Survivorship vs. Fractional Ownership

Joint Tenancy operates on the principle of survivorship. When one joint tenant dies, their interest in the property ceases to exist as a separate asset and vests immediately in the surviving joint tenant(s). This happens outside the probate process, meaning the property does not form part of the deceased’s estate for grant of representation purposes. For Inheritance Tax, however, the value of the share that “disappears” is still treated as a transfer of value at the date of death.

Under a Tenancy in Common, each co-owner holds a distinct, identifiable share—typically 50% each, but the split can be unequal (e.g., 60/40, 70/30). That share does not pass automatically; it is an asset of the deceased’s estate and must be administered according to the Will or the intestacy rules. This gives the owner the freedom to leave their share to a specific beneficiary, such as a child from a first marriage, rather than to the surviving co-owner.

The choice between the two is not irrevocable. A Joint Tenancy can be “severed” at any time by one party serving written notice on the other, converting the ownership into a Tenancy in Common. Severance is a common planning step when couples wish to protect the nil-rate band or ring-fence assets for children from a prior relationship.

How Joint Tenancy Affects IHT on the First Death

For a married couple or civil partners, a Joint Tenancy often produces the simplest IHT outcome on the first death. Because the entire property passes to the survivor by survivorship, no chargeable transfer occurs—transfers between spouses are exempt from IHT under the spouse exemption (Section 18, Inheritance Tax Act 1984). The property simply continues to be owned by the survivor.

However, this simplicity can mask a missed opportunity. The deceased’s nil-rate band (currently £325,000 per person, frozen until April 2030) and the Residence Nil-Rate Band (RNRB) of up to £175,000 are not “used” on the first death if everything passes to the spouse. Instead, they are transferred to the surviving spouse as a transferable nil-rate band. This works well for couples where the survivor will ultimately own the entire estate and can use both sets of allowances on their own death.

The risk arises when the survivor later remarries or needs long-term residential care. If the survivor’s estate exceeds the combined allowances (up to £1 million for a couple with a qualifying residence), the IHT liability at 40% can be substantial. Mrs A and Mr B, a couple with a £900,000 home held as Joint Tenants, saw Mr B die in 2023. The entire home passed to Mrs A with no immediate tax. On Mrs A’s subsequent death in 2025, her estate of £1.1 million (including the house) faced an IHT bill of £40,000 after using both nil-rate bands and the RNRB. Had they held as Tenants in Common and used a discretionary trust for Mr B’s share, the outcome could have been different.

Tenancy in Common and the Strategic Use of Nil-Rate Bands

Holding as Tenants in Common allows each co-owner to plan their share independently. On the first death, the deceased’s share (e.g., 50% of a £600,000 home = £300,000) does not automatically pass to the survivor. Instead, it can be directed by Will into a discretionary trust or directly to children, while still qualifying for the spouse exemption if left to the surviving spouse.

The strategic advantage lies in “using” the deceased’s nil-rate band and RNRB at the first death, rather than transferring them. If the deceased’s share is left to children or into a trust, the value of that share is set against the deceased’s own allowances. This can be particularly valuable when the property is worth more than the combined allowances, or when the survivor already has significant assets of their own.

For example, Mr C and Mrs D held their £850,000 home as Tenants in Common, each owning 50%. Mr C died in 2024. His Will left his £425,000 share to their two children. Because the share passed to non-spouse beneficiaries, Mr C’s RNRB of £175,000 and nil-rate band of £325,000 were fully utilised, leaving no IHT due on his death. Mrs D retained her 50% share, and the property was now owned by Mrs D and the children as Tenants in Common. On Mrs D’s later death, her estate was smaller, and the children already held their inheritance free of IHT on the first death.

This structure is especially relevant for blended families. A Tenancy in Common allows a parent to ensure that their share of the home passes to their own children, rather than to the surviving spouse who might later leave it to a different set of beneficiaries.

The Residence Nil-Rate Band: Interaction with Ownership Form

The RNRB, introduced in April 2017, provides an additional tax-free allowance of up to £175,000 per person for a qualifying residence passed to direct descendants (children or grandchildren). The RNRB is tapered by £1 for every £2 of net estate value above £2 million, disappearing entirely above £2.7 million.

The form of ownership directly affects whether the RNRB can be claimed on the first death. Under a Joint Tenancy, because the property passes automatically to the surviving spouse, the deceased’s share does not “go” to a direct descendant—it goes to the spouse. The RNRB is therefore not used on the first death but is transferred to the survivor. This is fine if the survivor’s estate will eventually pass to descendants.

Under a Tenancy in Common, if the deceased’s share is left directly to children or into a trust for their benefit, the RNRB can be claimed on the first death. This is particularly advantageous when the survivor’s estate is likely to exceed the £2 million taper threshold, or when the survivor might remarry and redirect assets away from the deceased’s children.

Mrs E, a widow with a £1.8 million estate, held her home as Joint Tenant with her second husband. When she died in 2023, her share passed to him, and her RNRB was lost entirely because the property did not pass to her children from her first marriage. Had she severed the Joint Tenancy and held as Tenants in Common, her Will could have directed her share to her children, preserving £175,000 of tax-free allowance.

Severing a Joint Tenancy: When and How to Act

Severance is the legal process of converting a Joint Tenancy into a Tenancy in Common. It can be done unilaterally by one co-owner without the consent of the other, provided written notice is served. The notice must be in writing, clearly state the intention to sever, and be delivered to the other co-owner. A simple recorded-delivery letter is sufficient in law, though many solicitors recommend a formal Deed of Severance for clarity.

Severance is often triggered by a change in personal circumstances: divorce or separation, the death of a child, a desire to protect assets for a specific beneficiary, or simply a review of estate planning. It is a zero-cost step for IHT purposes—no Stamp Duty Land Tax is triggered because no beneficial interest changes hands at the point of severance.

The timing of severance matters. If a couple is considering a Tenancy in Common to optimise IHT, the severance should occur well before any anticipated death. HMRC may scrutinise a severance carried out shortly before death as a “gift with reservation of benefit” if the deceased continued to occupy the property without paying market rent. For cross-border families managing UK assets alongside international accounts, some use platforms like Airwallex global account to handle multi-currency estate expenses, though the severance itself requires a UK solicitor.

Practical Steps for Cross-Border and Blended Family Situations

For individuals with UK property who are resident overseas, or for families where children are spread across jurisdictions, the ownership form becomes even more critical. A Joint Tenancy can create probate complications if the survivor is non-UK resident and needs to deal with the property without a grant of representation. A Tenancy in Common, by contrast, allows the deceased’s share to be administered under a UK grant, which is often simpler for non-resident executors.

Blended families should almost always hold as Tenants in Common. The default survivorship rule of a Joint Tenancy can inadvertently disinherit children from a first marriage. A Will that leaves the deceased’s share to those children, combined with a Tenancy in Common, ensures that the property is divided according to the deceased’s wishes, not by the default survivorship mechanism.

The use of a life interest trust or discretionary trust for the deceased’s share is also easier to implement with a Tenancy in Common. The trust can hold the share while allowing the surviving spouse to continue living in the property, balancing tax efficiency with practical occupation rights.

FAQ

Q1: Can I change from Joint Tenancy to Tenancy in Common without selling the property?

Yes, severance does not require a sale or any change in physical occupation. You simply serve a written notice on the other co-owner, or both parties sign a Deed of Severance. The Land Registry is then updated to reflect the new ownership form. The entire process typically costs between £150 and £500 in legal fees and takes 2–4 weeks.

Q2: If I hold as Tenants in Common, can the surviving spouse still live in the property after my death?

Yes, provided your Will grants them a right of occupation, either through a life interest trust or a specific provision allowing them to remain. Without such a provision, the beneficiaries (e.g., your children) could theoretically require the property to be sold. A properly drafted Will using a life interest trust ensures the surviving spouse can stay for life while the capital passes to your chosen beneficiaries.

Q3: Does severing a Joint Tenancy trigger an immediate IHT charge or Capital Gains Tax?

No. Severance is a change in the form of legal ownership, not a disposal of the beneficial interest. No IHT charge arises at the point of severance. For Capital Gains Tax, severance is also a no-gain/no-disposal event. The only tax implications arise on the subsequent death of one co-owner, depending on how the share is then dealt with.

References

• HMRC, 2024, Annual Inheritance Tax Statistics: 2023/24
• HMRC, 2024, Inheritance Tax Manual: IHTM15000 – Joint Property
• UK Government, 2023, Residence Nil-Rate Band: Technical Guidance
• Law Commission, 2022, Making a Will: Report on Inheritance and Property Rights