Why your British passport does not matter
The FIG regime has no domicile or nationality test. Eligibility rests entirely on your residence history under the Statutory Residence Test: you must have been non-UK resident for each of the 10 tax years immediately before the year you become UK resident again. A British citizen who left in 2014 and returns in 2026/27 qualifies on exactly the same terms as a foreign national arriving for the first time. The trap is a stray year of accidental UK residence inside that 10-year window, often an unplanned stretch of UK days during a family stay or a long visit home; a single resident year in the window breaks the claim.
Count the four-year window carefully
Relief runs for your first four consecutive tax years of UK residence, and the clock starts in the first of them whether or not you claim. Return in 2026/27 and your window is 2026/27 to 2029/30. If you resumed UK residence before the regime began on 6 April 2025, you only get what is left of your original window: a 2023/24 returner's window was 2023/24 to 2026/27, so they can claim only 2025/26 and 2026/27. Unused years are lost, and the window never pauses or extends, even if you leave again mid-window.
What claiming actually costs
The claim is made each year on the SA109 pages of your Self Assessment return; it is never automatic. For any year you claim, you give up the £12,570 Personal Allowance and the £3,000 Capital Gains Tax annual exempt amount in full, so with modest foreign income a claim can cost more than it saves and the decision should be modelled year by year. UK salary, UK rents and gains on UK property remain taxable throughout. For the full eligibility detail, worked numbers and the SA109 mechanics, see our full guide to the 4-year FIG regime.