How to leave UK tax residency, legally

Leaving UK tax residency isn’t a flight — it’s a test. HMRC runs the Statutory Residence Test (SRT) on each tax year, and the result is binary: resident, or non-resident. The only halfway is split year treatment. Get it right and you can be taxed as a non-resident from the day after you leave. Get it wrong and you stay on HMRC’s hook for the whole tax year, sometimes longer.

This is the version we run with members. It assumes you’re moving to a destination that taxes foreign income lightly — Thailand or Paraguay — and that you want the exit defensible under enquiry, not just done.

The SRT is the only test that matters

The Statutory Residence Test, in force since April 2013, replaced two decades of case law with a flowchart. HMRC runs it in three stages, in order:

1. Automatic overseas tests. Pass any one and you’re non-resident. Most relevant: fewer than 16 days in the UK if you were resident in any of the prior three tax years, OR fewer than 46 days if you were not, OR full-time work abroad with fewer than 91 UK days, fewer than 31 days working more than three hours in the UK, and no significant break.
2. Automatic UK tests. Fail the overseas tests and HMRC checks these. Spend 183+ days in the UK, have a UK home available for 91+ consecutive days, be present in it on at least 30 days of the tax year and spend fewer than 30 days in any overseas home across that period, or work full-time in the UK — and you’re resident.
3. Sufficient ties test. If neither automatic test resolves you, HMRC counts your “ties”: family in the UK, available accommodation, 40+ working days in the UK, 90+ days in either of the two prior tax years, more time in the UK than any other country (a tie only if you were resident in one of the three prior years). The ties allowed depend on your day count.

Read it, in order, every year. The SRT is the entire game.

The full-time-work-abroad route is the cleanest

Most CERØ members exiting the UK use the third leg of the automatic overseas tests: full-time work abroad. The legal definition is an average of 35 or more hours a week of work outside the UK with no significant break, fewer than 91 UK days in the tax year, and fewer than 31 days on which you work more than three hours in the UK.

For a freelancer or founder running a remote operation from Bangkok or Asunción, that’s almost always the natural shape of the year. The cleanest evidence trail is a calendar showing the working days, contracts dated post-departure, and invoices issued from your new entity.

Don’t try to thread the 183-day automatic test if the work-abroad route is open. The work test gives a clean answer; the day count alone is a fight you don’t want.

P85 — the form that closes the door

The P85 is HMRC’s “Leaving the UK” form: it tells HMRC you’ve left or are leaving, and claims back tax — mainly on UK employment income. Filing it doesn’t make you non-resident — the SRT does that. It is for people who don’t file Self Assessment: send it online once you’ve left, or print and post it before you go, with the date of departure and your new overseas address.

If you were employed, your P45 from your last employer goes with the P85. If you file Self Assessment for the year you leave — as the self-employed do — you don’t need a P85: the departure goes on the return’s SA109 residence pages, on paper or through commercial software, because HMRC’s own online return can’t take them. The exception is full-time work abroad for a UK employer for at least a full tax year, which needs both.

You’ll also need to:

• File the Self Assessment return (SA100) for the tax year of departure, including the SA109 residence pages — by 31 October after the tax year ends on paper, or 31 January through commercial software, since HMRC’s own online return cannot file the SA109.
• Report split year treatment on the SA109 if you meet one of its cases (more on this below).
• If you let out UK property, apply to the Non-Resident Landlord Scheme with form NRL1i to receive the rent without basic-rate tax deducted. The scheme turns on living abroad for six months or more a year, not on the SRT.
• Tell your ISA provider, as you can’t pay into an ISA once non-resident — the one exception is a Crown employee working overseas, and their spouse or civil partner — and the Student Loans Company if you’ll be away for more than three months.
• Check National Insurance before relying on it for your State Pension: since 6 April 2026 there are no voluntary Class 2 contributions for time abroad, and voluntary Class 3 (form CF83) for 2026/27 onwards needs either 10 years living in the UK in a row or 10 years of qualifying contributions — credits and voluntary contributions for other periods abroad do not count. Earlier tax years still go by the old three-year test, and gaps can only be filled for the past six tax years.

Split-year treatment — the rule that saves the year

The UK tax year runs 6 April to 5 April. If you leave mid-year, the default is that you’re either resident or non-resident for the entire tax year. Split year treatment, when it applies, divides the year into a UK part, taxed as a resident, and an overseas part, taxed for most purposes as a non-resident — so foreign income after departure falls outside UK tax, while UK income can still be taxed.

The eight cases are technical; three cover leaving. The most common for our members are Case 1 (starting full-time work overseas, which must make you non-resident the next year) and Case 3 (ceasing to have any home in the UK). Case 3 also needs fewer than 16 days in the UK for the rest of the tax year and, within six months, tax residence, daily presence or your only home in one country — and its overseas part starts the day your UK home goes, not the day you fly. Keep the evidence: contracts, the lease ending, the council tax closure.

Without split year treatment, you are resident for the whole tax year and your income after departure stays UK-taxable. The treatment isn’t a choice — if you meet a case, it applies — but you report it on the SA109, naming the case in the “any other information” box, since the form has no case-number box.

Exit charges — the part most people miss

The UK doesn’t have a general exit tax on personal assets, but it does have several disposal charges that bite on departure:

• Capital Gains Tax on UK property. Non-residents owe CGT on UK-situated land and buildings, even after departure. Plan disposals around the move.
• Temporary non-residence rules. If you come back after five years or less abroad — measured between your periods of sole UK residence, so the clock starts on your departure date only where split year treatment applies — having been UK resident in at least four of the seven tax years before you left, certain income and gains from your time away — capital gains, close-company distributions and pension lump sums among them — are taxed in the year you return (TCGA 1992 s.1M for gains). For returns on or after 6 April 2026 the old carve-out for close-company dividends paid out of trade profits earned after departure is gone. Founders cashing out a UK company should plan to stay away for more than five years.
• EIS deferral relief. If you move abroad within three years of the shares being issued (or of the company starting to trade), the gain you deferred into EIS shares becomes taxable, unless you left for a job done entirely abroad and return within three years without selling. Moving abroad does not by itself withdraw EIS or SEIS income tax relief.
• Pensions and ISAs. You can keep an ISA open, it keeps its UK tax relief and you can still move it between providers, but you can’t add money once you’re non-resident, and you can subscribe again only if you come back. That relief is a UK one: your new country taxes the income and gains under its own rules, and Thailand, which taxes residents on the foreign income they bring in, gives the ISA wrapper no recognition at all. A UK pension such as a SIPP can stay too, and if you were UK resident when you joined the scheme, relief on new contributions survives the five tax years after the last one in which you were resident (Finance Act 2004, s. 189(1)(c) — both halves matter, so a scheme opened after you left gets none). It is relief on £3,600 gross a year, £2,880 paid in, unless you still have UK earnings chargeable to UK tax. Withdrawals are the harder half: the 1981 UK–Thailand treaty has no article for private pensions and no “other income” article, so it never decides where they are taxed. The UK deducts tax under PAYE, Thailand taxes what you bring in, and the relief is the credit for UK tax that Thailand gives under Article 23.

These aren’t reasons not to leave — they’re reasons to sequence the leaving. A clean exit times the disposal events, not just the flight.

What your destination has to do

The UK exit only sticks if you’re substantively resident somewhere else. For Thailand:

• 180+ days in the country, documented (entry stamps, lease, bank account).
• A Thai tax-residency certificate at year-end. We pull this for every member who clears the threshold.
• A clean Thai PIT filing — even if your effective rate is single digits.

For Paraguay, the cédula does the heavy lifting, plus 120+ days of presence and a certificado de residencia fiscal.

A foreign tax-residency certificate doesn’t decide UK residence — the SRT does — but it supports treaty relief, and tax residence abroad is one of the ways to meet split year Case 3. Together with a correctly reported split year, it is what makes the file defensible.

A 14-week version of the timeline

Most CERØ members run roughly this calendar:

• Week 1. Diagnosis call. We map your income sources, family situation, UK property, and timing constraints. You get a written plan.
• Weeks 2–4. UK-side prep. Self Assessment filings, P85 readiness, lease termination, council tax closure, employer notice, NRL1i if applicable.
• Weeks 4–8. Destination paperwork. DTV file or cédula application, bank account, lease.
• Week 8. Plane.
• Weeks 8–14. First days on the ground. Local registrations, lease, residency certificate trigger.
• After the tax year ends (5 April). Self Assessment with the SA109 and the split year case, by 31 October on paper or 31 January through commercial software — or, if you don’t file Self Assessment, the P85, which you can send as soon as you’ve left.
• Year +1. Foreign tax-residency certificate in hand — the evidence that backs your treaty position and any DTA relief claim (the SRT, not the certificate, is what makes you non-resident).

The piece nobody tells you

The hardest part of leaving the UK isn’t the SRT — it’s the appearance of leaving. If your London flat is “available to you” through a friend, your trips back run to four weeks a year, and your invoices still go to a UK accountant, your file is wobbly. HMRC’s residency enquiries focus exactly on this kind of half-exit.

The clean version means closing the UK home, terminating the council tax, deregistering the GP, cancelling the gym, moving the operating company, and not going back to spend half of December in Notting Hill. We rebuild this end-to-end for every member.

Where to go from here

If you want to see the destination maths first, run the Thailand tax calculator — it estimates what changes once HMRC stops taxing you as a resident. Or read the Thailand vs UK comparison for the side-by-side.

If you already know you’re moving and want the free diagnosis call, book it here. We’ll tell you on the call whether your situation is one we can run cleanly, or whether you need a different shape.