The short answer: tell HMRC through the route that fits your filing position, then determine residence using the full Statutory Residence Test. Keep tracking UK-source income after departure: non-residence does not switch off UK tax on rent, some pensions, employment or gains.
P85 or Self Assessment: choose the right route
These are reporting routes, not ways to choose your tax residence. Start with your normal filing position, then check whether your work creates an exception.
You do not normally file Self Assessment
HMRC generally directs you to form P85. You will need departure and employment details plus your P45 if you have one. HMRC uses the information to update its records and check whether PAYE has over- or under-collected tax.
You normally file Self Assessment
Report the departure in your return and complete SA109. HMRC's own online filing service does not support SA109, so use compatible software, an agent or a paper return. HMRC currently says you should also complete P85 if you will work full-time abroad for a UK-based employer for at least one full tax year.
Continuing for a UK employer? The facts can affect PAYE and the reporting route. Give HMRC the actual overseas-working arrangement, not simply a new postal address.
How the Statutory Residence Test works
Run the test for each tax year in order. Start with the automatic overseas tests, then the automatic UK tests, then—only if neither decides the result—the sufficient ties test. Days alone are not the whole calculation.
Automatic overseas tests
Examples include spending fewer than 16 UK days after being UK resident in one or more of the previous three tax years; fewer than 46 days after not being resident in any of those years; or qualifying full-time work overseas with tight limits on UK days and UK workdays.
Automatic UK tests
These include 183 or more UK days, having a qualifying UK home with no qualifying overseas home, or meeting the full-time UK work test.
Sufficient ties
Family, accommodation, work, 90-day and country ties are combined with UK day count. The more prior UK connection you have, the fewer days may be needed for UK residence.
Split-year cases
After residence is established, check whether a statutory split-year case applies. A qualifying year can divide into UK and overseas parts, but the treatment is not elected simply because it feels fair.
Keep evidence as you go: travel records, boarding passes, calendars, accommodation, contracts and work-hour records. Reconstructing a year after an HMRC query is much harder.
What the UK may still tax after you leave
| Income or gain | UK position to check | Where to go next |
|---|---|---|
| UK property rent | Usually remains UK taxable; the Non-resident Landlord Scheme affects deduction at source. | Rent vs sell guide |
| UK property sale | A non-resident normally reports a disposal within 60 days, even if no tax is due. | Property tax timeline |
| Pension income | UK rules and the relevant treaty determine where different pension types are taxed. | Pensions abroad |
| UK work or business | Duties performed in the UK and permanent-establishment questions can preserve UK taxing rights. | Map workdays and get tailored advice where needed. |
| Interest, dividends and gains | Domestic rules, temporary non-residence and treaty terms can interact. | ISAs and investments |
Double taxation is relief, not a promise of no tax
The UK has double-taxation agreements with Thailand, Malaysia, Vietnam, Indonesia and the Philippines, but the wording is country- and income-specific. A treaty may give one state the primary right to tax, preserve rights for both with a credit, or treat government-service pensions differently.
- Establish domestic residence in both countries before applying treaty tie-breakers.
- Identify the exact income article: employment, business, pensions, property, dividends and gains are not interchangeable.
- Keep foreign tax certificates and payment evidence for any credit or repayment claim.
- Use HMRC's treaty and residence forms only after confirming the route for that country.
National Insurance changed in April 2026
For periods abroad from 6 April 2026, voluntary Class 2 was largely removed for employees and most self-employed people abroad. A new application to pay voluntary Class 3 normally requires either ten continuous years living in the UK or ten qualifying years on the National Insurance record.
Check before paying
Open your National Insurance record and State Pension forecast. A gap does not always improve your pension when filled, particularly with contracted-out or mixed records.
Transitions matter
People already paying Class 3 abroad can continue without the new test. Existing Class 2 payers may have a time-limited route into Class 3 under previous criteria; read HMRC's transitional guidance before 6 April 2027.
Plan for a possible return, too
Leaving cleanly includes keeping the evidence you may need if the family returns. UK temporary non-residence rules can bring some gains and income realised while abroad into charge after a return, particularly where the period away is short.
Before a large transaction
Check the UK and destination treatment before selling a company, shares or another major asset. Do not rely on the departure date alone.
Before moving back
Review the length of non-residence, the years before departure and what you received or realised while away. Keep tax returns, residence calculations and transaction records.