The Great UK Inheritance Tax Reform: The New Long-Term Residence Regime from 2025

Introduction: The End of a Fiscal Era

The United Kingdom's tax landscape is undergoing one of its most profound transformations in decades. Starting April 6, 2025, the historic concept of "domicile" and its derivative, "deemed domicile", will cease to be the governing criteria for determining worldwide liability under the UK Inheritance Tax (IHT). In their place, the British legislature, through the Finance Act 2025, introduces a model based on tax residence, redefining the taxation of assets situated outside British territory.

This regulatory shift represents a significant change from a centuries-old legal tradition. Historically, individuals not domiciled in the UK (commonly known as "non-doms") enjoyed a favorable position, as their foreign assets remained outside the scope of IHT, limiting their estate tax exposure to assets located within the UK. With the entry into force of the new rules, individuals who qualify as a "long-term resident" (LTR) will be subject to IHT on their worldwide estate, including directly owned foreign assets.

The New Long-Term Residence (LTR) Criterion

The core of the reform lies in the creation of the long-term resident status for Inheritance Tax purposes. Under the new section 6A of the Inheritance Tax Act 1984 (IHTA 1984), introduced by the Finance Act 2025, an individual will be treated as an LTR if they have been a UK tax resident for at least 10 out of the last 20 tax years immediately preceding the chargeable event (such as death or a chargeable lifetime transfer).

This 10-year threshold represents a reduction compared to the previous "deemed domicile" regime, which required the taxpayer to be resident for at least 15 out of the preceding 20 tax years. By shortening this timeframe to a single decade, the UK government expands the universe of foreign taxpayers whose global estates will be exposed to the general 40% tax rate upon death.

The Mechanics of the "Tail Period"

One of the features of the new regime is that losing UK tax residence does not immediately remove a taxpayer from the scope of IHT on their worldwide assets. The legislation establishes a transitional "tail period", during which a former resident who qualified as an LTR remains within the scope of the tax after leaving the country.

The duration of this tail period varies proportionally based on the years of prior residence in the UK, ranging from 3 to 10 tax years:

• For individuals who were resident between 10 and 13 tax years, the tail period will be the minimum: 3 tax years.
• From the fourteenth year of residence, the tail period increases by one tax year for each additional year of prior residence, up to a maximum of 10 tax years of exposure for those who have resided in the UK for 20 years.

For example, if a person was UK resident for 15 out of 20 tax years on leaving the UK, they would remain in scope for 5 tax years; if the chargeable event (such as death) occurs within that 5-year window, their directly owned foreign assets will be subject to the general rate of IHT.

Differences Table and Legal Boundaries

To avoid common confusion in international estate planning, it is advisable to clearly distinguish the new LTR status from other current or repealed tax and civil concepts.

It is important to emphasize that the long-term resident (LTR) status must not be confused with the former deemed domicile status, as they are legally distinct concepts with different temporal thresholds. Likewise, the fiscal concept of LTR is legally distinct from the common law concept of domicile, which remains fully active for non-tax purposes. The abolition of domicile as a test for tax liability is strictly for fiscal purposes (IHT, FIG, OWR), meaning that civil domicile of origin or choice will continue to govern the law applicable to the general civil succession.

Resetting the Status: The Tail Period Rule

For former residents wishing to eliminate their exposure to IHT on foreign assets upon returning to the UK, the law imposes a rigorous requirement. A consecutive period of non-UK tax residence equivalent to the applicable "tail period" (between 3 and 10 years) is required to fully reset the LTR status. If an individual returns to the UK before completing these consecutive years of absence, their prior years of residence will continue to count within the 20-year lookback period, potentially bringing them back into the scope of IHT immediately.

The rule dictates that for those not resident at the date of the chargeable event (including death) where the years of non-residence are not consecutive, the test under Section 6A(2) of the IHTA 1984 is applied and the individual will remain a long-term UK resident until the required number of years of consecutive non-UK residence has passed (IHTA 1984, Section 6(3)).

Crucial Distinction: The 2027 Pension Reform

In analyzing UK tax reforms, wealth advisors must maintain a clear separation of legislative timelines. The entry into force of the general LTR rules for foreign assets on April 6, 2025, must not be confused with the reform of the Inheritance Tax treatment of pensions, which is regulated by subsequent legislation and takes effect on a different date.

Indeed, the government has announced reforms to the Inheritance Tax Act 1984, Finance Act 2004 and Income Tax (Earnings and Pensions) Act 2003 to bring pensions into the scope of Inheritance Tax for deaths on or after April 6, 2027. This reform aims to remove distortions that have led to pension schemes being increasingly used and marketed as tax planning vehicles to transfer wealth intergenerationally free of IHT, rather than for funding retirement. Therefore, while an LTR's direct foreign estate becomes exposed to IHT starting April 2025, accumulated pensions will not enter the IHT calculation until April 2027.

Technical Amendments and the Role of International Treaties

Given the magnitude of the shift to a residence-based model, the British government has had to introduce legislative adjustments to ensure the consistency of the system. These measures will make minor corrective amendments to the broader residence-based tax regime established in the Finance Act 2025 to ensure it operates as originally intended, without altering the underlying policy position. These corrections ensure that the associated reliefs and the Temporary Repatriation Facility function fairly and remain internationally competitive.

On the other hand, the practical application of these rules on specific foreign assets may be altered by the Double Taxation Conventions in force between the UK and other jurisdictions. Certain legacy treaties (such as those with India or Pakistan) contain specific provisions based on civil domicile that prevail over the new domestic residence-based rules of the UK. In these cases, the treaty limits the UK's power to tax assets situated in those countries, even if the deceased qualifies as an LTR under domestic British law. Each case must be analyzed meticulously under the prism of the applicable treaty.

Practical Implications for High-Net-Worth Individuals (HNWIs)

The transition to the long-term residence model demands a review of estate planning structures for international HNWIs with UK connections. Priority actions include:

1. Historical Residence Audit: Calculate the number of UK tax residence years within the last 20 years to determine the date on which LTR status will be acquired, or, if already departed, the duration of the applicable tail period.
2. Double Taxation Treaty Evaluation: Analyze whether foreign assets are located in jurisdictions with favorable IHT treaties that may mitigate the 10-year rule.
3. Early Exit Planning: For residents approaching the 10-year threshold, evaluate the feasibility of relocating tax residence outside the UK before becoming an LTR, to avoid the activation of the tail period on their worldwide estate.
4. Restructuring of Trusts: Evaluate the impact of the end of "Excluded Property" status for foreign assets held in trusts. Under the new regime, IHT protection will depend on whether the settlor is treated as an LTR at the time of the chargeable event, requiring a thorough review and potential restructuring of existing trusts before the settlor acquires LTR status.

This new regulatory landscape redefines the rules for the global mobility of capital and individuals, consolidating a system where physical presence over time, rather than the subjective intent of belonging to a territory, determines one's contribution to the British treasury.