The default rule: worldwide taxation
Once you become UK tax resident, the default position is that you pay UK tax on your worldwide income and gains, not just your UK earnings. Your residence status is decided by the Statutory Residence Test, and in your arrival year split-year treatment may divide the year into a non-UK part and a UK part, so the year you move needs careful handling.
The big exception: the 4-year FIG regime
From 6 April 2025 the 4-year FIG regime replaced the old non-dom remittance basis. If you were non-UK resident for the 10 consecutive tax years immediately before becoming resident, you can claim full UK tax relief on qualifying foreign income and gains (foreign dividends, interest, rents and gains arising from 6 April 2025) for your first four years of residence, and bring the money into the UK freely with no remittance charge. Because the test is residence-based, not domicile-based, returning British expats qualify too. UK-source income remains taxable throughout, and foreign employment income sits outside the FIG claim: it is relieved separately through Overseas Workday Relief.
The trap: the claim is annual and has a price
The relief is not automatic. You must claim it each year on the SA109 residence pages of your Self Assessment return, and each claim costs you your £12,570 Personal Allowance and £3,000 Capital Gains Tax annual exempt amount for that year. With large foreign income that price is trivial; with modest foreign income the lost allowances can cost more than the relief is worth, and the right answer can change from year to year. Before filing, confirm your 10-year residence history under the Statutory Residence Test and model the numbers both with and without the claim.
