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 your year, and the result is binary: resident, or non-resident. There is no halfway. Get it right and the file closes the day you board. 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 territorial-tax destination — 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 and fewer than 31 working days in the UK.
2. Automatic UK tests. Fail the overseas tests and HMRC checks these. Spend 183+ days in the UK, have a UK home for 91+ days while spending 30+ nights in it, 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. 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 roughly 35+ hours a week of work outside the UK, fewer than 91 UK days in the tax year, and fewer than 31 working days 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. Filing it doesn’t make you non-resident — the SRT does that — but it tells HMRC you’ve left, triggers your tax code change, and starts any refund owed for the part-year. File it once you’ve actually left, 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 were self-employed, file it alongside your final Self Assessment.

You’ll also need to:

• File your final Self Assessment (SA100) for the tax year of departure, including the SA109 residence supplement.
• Claim split-year treatment if you qualify (more on this below).
• Notify HMRC if you have ongoing UK property income — non-resident landlords have a separate scheme (NRL1).
• Settle any outstanding NICs and check whether voluntary contributions abroad make sense for your state pension.

Split-year treatment — the rule that saves the year

The UK tax year runs April 6 to April 5. 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-resident part and an overseas part — meaning post-departure foreign income isn’t UK-taxable.

The eight cases for split-year treatment are technical, but the most common ones for our members are Case 1 (starting full-time work overseas) and Case 3 (ceasing to have a home in the UK). Each requires specific evidence: contracts, lease termination, council tax closure, utility cancellations.

Without split-year treatment, your full year of post-departure income is UK-taxable. The case has to be claimed on the SA109; HMRC doesn’t apply it automatically.

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 return to UK residence within five complete tax years, certain gains and distributions realised while non-resident become UK-taxable retroactively. Founders cashing out a UK company should plan a clean five-year window.
• EIS/SEIS clawback. Disposals of EIS or SEIS shares while non-resident can lose tax relief if conditions aren’t met.
• Pension and ISA implications. ISAs lose their tax-free wrapper for new contributions once you’re non-resident. SIPPs are usable but reporting differs.

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 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.

HMRC accepts a foreign tax-residency certificate as strong evidence of where your residence has gone. The combination of split-year claim + foreign certificate is what closes the file.

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, NRL1 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.
• April 5 of departure year. Self Assessment with split-year claim and SA109. P85 filed.
• Year +1. Foreign tax-residency certificate in hand — the document HMRC actually accepts as proof.

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 math first, run the Thailand tax calculator — it estimates what changes when HMRC stops taking 40-47%.

If you already know it’s a move and want the 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.