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The short answer
If you move from Nigeria and become UK resident part-way through a tax year, split-year treatment can divide that year into an overseas part and a UK part, so you are not treated as resident for the months before you arrived. It applies only if you are UK resident for the year and your situation fits one of HMRC's arrival cases, most often starting full-time work in the UK or starting to have your only home here. You show it on the SA109 residence pages.
UK residence is decided for a whole tax year, which runs from 6 April to 5 April. Someone who arrives from Lagos in September and passes the 183-day test is UK resident for the entire year from 6 April. Without a special rule, income from April to August, earned while you were still living in Nigeria, could be within UK tax. Split-year treatment exists to stop that. This is information, not tax advice.
First condition: you must be UK resident for the year
HMRC's SA109 notes for 2025 to 2026 say split-year treatment is only due if you are UK resident for the year. So the first step is the statutory residence test. If you arrive very late in the tax year and are not resident for that year, LITRG's guidance says to consider split-year treatment for the following year instead.
The arrival cases
There are eight split-year cases in all. Cases 1 to 3 cover leaving the UK; cases 4 to 8 cover arriving. LITRG's guidance summarises the arrival cases as follows.
| Case | When it can apply | Extra condition |
|---|---|---|
| Case 4 | You start to have a home only in the UK, with no home in any other country for the rest of the year | Conditions on the overseas part |
| Case 5 | You start a 365-day period of full-time work in the UK | Conditions on the overseas part |
| Case 6 | You return after a period of non-residence caused by full-time work overseas, of no more than five tax years | UK resident in the following year |
| Case 7 | Your partner qualifies under Case 6 and you move to join them | UK resident in the following year |
| Case 8 | You start to have a home in the UK for the rest of the year and the whole of the following year | UK resident in the following year |
For most Nigerians moving on a work visa, Case 5 (starting full-time UK work) or Case 4 (having your only home in the UK) is the relevant one. Cases 6 and 7 apply to people who lived in the UK before, left to work abroad, and came back. If more than one case could apply, LITRG says the earliest date generally wins, and in simple cases the UK part usually starts from the earlier of starting full-time UK work and starting to have a UK home.
Worked example
Example only. Ada lived and worked in Lagos until August. She lands in the UK on 1 September, starts a full-time nursing job on 8 September and signs a tenancy on 1 September after giving up her rented flat in Lagos. She has no other home abroad. She is in the UK for well over 183 days before 5 April, so she is resident for the year. Case 4 could give a UK part from 1 September (only home in the UK) and Case 5 from 8 September (full-time work). The earlier date, 1 September, would generally be the start of the UK part. Her Lagos salary for April to August falls in the overseas part.
Each case also has conditions about the overseas part of the year, set out in HMRC's Residence, Domicile and Remittance manual. Check them before relying on a date, because a trip to the UK earlier in the year, or keeping a home in Nigeria, can change which case applies.
Showing it on your tax return
- Complete the SA109 residence pages with your Self Assessment return.
- Tick box 3 to say split-year treatment applies.
- Enter the date the UK part of the year begins in box 6.
- State which case applies in the 'Any other information' box, box 54. If more than one case may apply, tick box 3.1 and explain in box 54.
- In box 10, the day count covers only the overseas part of the year.
The SA109 notes also say the ties box, box 12, is only needed if you tick box 3 for Case 4 or Case 8.
How this links to other first-year rules
- The four-year FIG regime. LITRG's FIG guidance says a split year counts as a year of UK residence, so it uses up one of your four years. See the FIG regime for new arrivals.
- Nigerian income after you arrive. Rent, interest or dividends from Nigeria that arise in the UK part of the year are reported in the usual way; see declaring Nigerian income.
- The treaty. LITRG notes that double tax agreements may modify the split date, for example if you are also resident in Nigeria for part of the year. The UK–Nigeria treaty guide covers the tie-breaker.
What to check first
- Confirm you are UK resident for the year of arrival.
- Write down your dates: arrival, job start, tenancy start, and when any Nigerian home ended.
- Match them against cases 4 to 8.
- Keep evidence: employment contract, tenancy, flight records.
Questions people ask
What is split-year treatment in the UK?
A rule that divides a tax year into an overseas part and a UK part for someone who arrives in or leaves the UK, so they are not taxed as resident for the whole year.
Is split-year treatment automatic?
It applies when you meet a case's conditions, but you must show it on the SA109 pages: tick box 3, give the date in box 6 and state the case in box 54.
Which split-year case applies if I came to the UK for a job?
Usually Case 5 (starting full-time work in the UK) or Case 4 (starting to have your only home in the UK). The earliest qualifying date generally wins.
Does a split year count as one of my four FIG regime years?
Yes. LITRG's guidance says split years count as years of UK residence for the FIG regime.
Sources
- SA109 Notes 2026: Residence and FIG regime pages, tax year 2025 to 2026, HMRC · accessed Oct 2026
- Split year treatment: arriving in the UK, LITRG (updated 6 April 2026) · accessed Oct 2026
- Foreign income and gains regime (tax years from 2025/26), LITRG (updated 6 April 2026) · accessed Oct 2026
This article is general information, not financial, legal or tax advice. Products described are provided under the terms on this site and are subject to regulation and eligibility.