The UK's New Inheritance Tax Residence Tail: How Long IHT Follows You After You Leave (2026)

The 2025 reforms did something under-appreciated amid the non-dom headlines: they rebuilt inheritance tax around residence. Domicile, the old anchor, is gone from IHT, replaced by a long-term residence test, and, crucially, by a tail that keeps worldwide IHT exposure alive for years after you leave the UK (HMRC policy paper). For anyone planning a departure, this changes what needs counting: not just days in a year, but years of residence across two decades. Updated 5 August 2026.

The test: 10 of the last 20 years

From 6 April 2025 you are a long-term resident for IHT if you were UK tax resident in at least 10 of the previous 20 tax years. Long-term residents face IHT on worldwide assets; others face it on UK-situated assets only. Each year's residence status is determined by the Statutory Residence Test, which means the day-counting machinery in our SRT guide now has estate-tax consequences too: a marginal year that tips resident can be the year that makes you long-term resident.

The tail: three to ten years after leaving

Leaving does not end it. A long-term resident who departs remains within worldwide IHT for a period that scales with how long they were resident: three tax years for someone resident 13 years or fewer, rising by one year for each additional year of residence up to the full ten-year tail at 20 years. Long-term resident status also falls away entirely after ten consecutive non-resident years. The planning consequence is blunt: for a long-settled leaver, dying within a decade of departure can leave a worldwide estate inside UK IHT, and the calendar of residence years, provable year by year, is what the exposure window is computed from.

What this means in practice

• Leavers need a residence history, not a vibe. Which of the last 20 tax years were UK-resident under the SRT is now a question your executors may need answered precisely.
• Marginal years matter twice. A borderline SRT year affects that year's income tax and your long-term-resident count.
• The tail interacts with the move. Pair this with the leaving-the-UK guide and, for the popular destination, the Dubai day-count guide.

Count the years by counting the days

Residence years are built from day counts, and reconstructing them a decade later is miserable. The Days Monitor iPhone app keeps the day-by-day record continuously, which is what makes each year's SRT position, and therefore your 10-of-20 count and tail, provable rather than arguable. Check any single year with the free Statutory Residence Test tool. Download it on the App Store.

Sources

• HMRC, Changes to the taxation of non-UK domiciled individuals (residence-based IHT) (accessed 5 August 2026)
• HMRC, RDR3: Statutory Residence Test (accessed 5 August 2026)

This article is general information, not legal, tax or immigration advice. Rules change, enforcement varies, and your facts matter. Verify current requirements with the official sources linked above and confirm your position with a qualified professional before acting.