The TL;DR
You've made the decision. You know where you're going. The last thing between you and a clean start is a small stack of UK admin most people either skip or get wrong.
This guide covers the five things HMRC won't do for you, whether you're going for six months or for good: what to file, who to notify, and what to keep so your tax record is settled cleanly before you leave.
Do it once, do it properly, and you're free.
Last checked: October 2026.
Covered in this article
1. Is this guide for you? 📍
How much you need to do depends on how long you're going. Find your timeframe.
🎒 1 to 3 months
Often no immediate HMRC action, but check your position. For an ordinary short trip there's often no immediate need to file a P85 or update your residency status. That said, UK residence is determined under the Statutory Residence Test, which looks at days in the UK, work patterns, home and ties, not trip length alone. What matters most now: employer approval in writing; travel insurance covering your trip length; and a record of your days in and out of the UK. Worth reading first: our guide to working abroad for your UK employer covers the short-trip checklist in full.
💼 3 to 6 months
Start getting organised. Many countries use 183 days as a common residence threshold, but local rules vary and some apply earlier, so it's not a universal safety net. If you've stopped working for your UK employer, a P85 or Self Assessment update is likely relevant; keep a clear record of every day in and out of the UK; and check your travel insurance still covers your length of stay.
🧺 6 to 12 months
This guide is written for you. For most people leaving for this long, notifying HMRC through P85 or Self Assessment is the right step, particularly if you're due a refund from UK employment or want your residency position on record. Split-year treatment is likely relevant and your UK tax position needs settling before you go. Work through the whole guide and complete the checklist before you leave.
📦 Over a year, or a permanent move
Everything here, plus professional advice. All the steps apply. At this length you also need to consider tax residency in your new country (likely to apply), UK State Pension entitlement and voluntary NI contributions, and pension planning and any employer payroll obligations. Book a consultation with an expat tax adviser before you leave; the adviser section covers who to call.
💡 Not sure which applies?
If you haven't set a return date, treat yourself as the 6-to-12-month category and work through the guide in full. Getting your position on record before you leave is considerably easier than correcting it later.
2. The 5 things HMRC won't do 📋
HMRC won't follow up, remind you, or chase you on any of these. Most people don't find out they needed to act until months after they leave, when it costs considerably more to fix.
1. 📒 Start a travel log
HMRC counts any day you're in the UK at midnight as a "present" day for Statutory Residence Test purposes. If they ever query your status, your travel log is your primary evidence. Without it, you're reconstructing months of movements from bank statements and boarding passes: messy, expensive and unconvincing.
Log these three things weekly, starting now: the date and your country at midnight; approximate UK work hours if relevant; and any notable changes.
What counts as a notable change? The SRT uses "ties" to determine your residence when day counts alone aren't conclusive. Anything showing where your life is centred is worth recording:
Starting or ending a UK job or contract
Signing, renewing or ending a UK lease or tenancy
Buying or selling UK property
Registering at an overseas address (rental agreement, utility bill, local registration)
Opening a bank account or joining a gym, club or GP abroad
A child starting school in another country
A partner or family member moving abroad with you
A simple spreadsheet works. The key is that it's consistent and contemporaneous; starting from memory months later isn't the same thing.
2. 📄 File your P85 or Self Assessment
HMRC won't update your residency status automatically. PAYE keeps deducting as if you're still UK-resident until you tell them otherwise. Which route you use depends on your situation, and in some cases both forms are required.
🏢 Employed and paid through payroll (PAYE): form P85 is most likely your route. It notifies HMRC of your departure and processes any refund from UK employment. Already left? Apply online at gov.uk/p85. Not yet left? GOV.UK says you need to print and post the form. No P45 because you're continuing with a UK employer abroad? You may still need to complete P85. HMRC's reply-date checker currently shows about three weeks to process it, online or by post.
💼 Freelance, contractor or company director: use Self Assessment with SA109. Use the SA109 residence pages to declare your departure date and split-year position. SA109 doesn't appear automatically, so add it yourself or ask your accountant, and note HMRC's own online service doesn't support SA109 (use commercial software, a professional, or file by post).
Exception: if you're going to work full-time abroad for a UK-based employer for at least one full tax year, GOV.UK says you may need to complete P85 as well as file Self Assessment with SA109.
⚠️ Worth knowing: the right approach depends on your specific situation. If you're unsure whether P85, SA109, or both apply, confirm with a tax adviser before filing.
3. 🧾 Sort your National Insurance
Once you stop paying NI in the UK, your State Pension entitlement stops building, and HMRC won't flag this or suggest you top it up.
For time abroad from 6 April 2026, you can only pay voluntary Class 3, at £18.40 per week for 2026/27 (about £956.80 for a full year). Class 2 can no longer be paid for time abroad.
To pay from abroad, GOV.UK says you need to have lived in the UK for 10 years in a row or paid 10 years of qualifying contributions in total.
If you already paid voluntary contributions for earlier years, or aren't sure what applies to you, contact the HMRC National Insurance team before you leave.
Each missing year costs you in retirement. Sort this before you leave, not after.
4. 🤝 Check your double-tax agreement
The UK has almost 130 tax treaties to prevent the same income being taxed twice, but relief isn't automatic: you have to claim it. Two things to check before you go:
Does a treaty exist? HMRC publishes the full list; if your destination isn't on it, any ongoing UK income may be taxed in both countries.
Do you have ongoing UK income? Rental income, dividends, pensions and investments keep paying after you leave. If so, this is essential; if you're leaving with no UK income continuing, it's lower priority.
5. ✂️ Claim split-year treatment
Most people leave mid tax year. The UK tax year runs 6 April to 5 April, so if you leave in October you have six months of income to account for. Where the statutory conditions are met, split-year treatment divides the year in two:
6 April to your departure date: UK resident, worldwide income taxable in the UK.
Departure date to 5 April: non-resident, only UK-source income taxable.
This doesn't apply automatically; it depends on which statutory case under the SRT you meet. Check HMRC's RDR3 guidance, linked in Resources.
💡 Worth knowing: earn £3,000 a month and leave in October? That's roughly £15,000 earned abroad before the April year end. Getting your split-year position right means that income is assessed correctly rather than sitting in the wrong part of your tax record.
