Cross-Border Tax Accountants: directory of firms

Gov.uk sets out automatic UK tests: spending 183 or more days in the UK in the tax year; having your only home in the UK for 91 days or more in a row and staying in it for at least 30 days of the tax year; or working full-time in the UK for any period of 365 days with at least one day of that period falling in the year being checked.

There are automatic overseas tests that point the other way. Spending fewer than 16 days in the UK, or fewer than 46 if you have not been UK resident in the three previous tax years, makes you non-resident. So does working abroad full-time, averaging at least 35 hours a week, while spending fewer than 91 days in the UK of which no more than 30 were spent working.

If neither set of automatic tests settles it, the sufficient ties test combines day count with connections such as work and family. The arithmetic is unforgiving, and keeping a contemporaneous record of travel dates is the single most useful habit for anyone near a threshold.

On 6 April 2025 the four-year foreign income and gains regime replaced the remittance basis. It is available to a qualifying new resident: someone who is UK tax resident under the statutory residence test and still within their first four years of UK residence following at least ten consecutive tax years of non-UK residence.

A claim must be made for each year the relief is wanted, and it runs for a maximum of four consecutive tax years from the year residence began. Unused years cannot be carried forward, and a year of temporary departure means the regime is unavailable for that year.

There is a trade. Claiming means giving up tax-free allowances for Income Tax and Capital Gains Tax, along with Married Couple's Allowance, Marriage Allowance and Blind Person's Allowance. Whether the claim is worth making is an arithmetic question that has to be answered year by year.

Two countries can each have a legitimate claim on the same income. The UK's network of double taxation agreements allocates taxing rights between them, and gov.uk notes that where your country of residence taxes your UK income, relief may be available so that you are not taxed twice on the same amount.

Relief is not automatic. It usually has to be claimed, sometimes in both countries, sometimes with a certificate of residence, and frequently within a time limit. Non-residents may still be entitled to a UK Personal Allowance, and where too much tax has been deducted a repayment can be claimed using form R43 or through a Self Assessment return.

Non-residents remain liable on UK pensions, rental income, savings interest and wages, while State Pension and interest on UK government gilts are normally outside the charge.

Income tax residence and social security liability are decided separately, and a person can easily be resident for tax in one country and paying social security in another. Where the UK has an agreement with the country concerned, a certificate of coverage shows that National Insurance is being paid in the UK, so contributions are not owed twice.

Without an agreement, gov.uk sets out a 52-week rule: UK National Insurance is due for the first 52 weeks abroad if you are working abroad temporarily, your employer has a place of business in the UK, you are ordinarily resident in the UK, and you were living in the UK immediately before starting the work.

Voluntary contributions can be paid while abroad to protect State Pension entitlement. That is a long-term decision worth taking deliberately rather than discovering decades later.