How to Choose the Best UK Tax Adviser for Expats

Key points

Expat tax first has to answer where you are resident and which country taxes each type of income.

✓ Look for membership of a professional body such as the Chartered Institute of Taxation, the ATT, the ICAEW or ACCA, and check its member directory.

✓ Under Finance Act 2026, anyone paid to deal with HMRC for a client must register with HMRC.

✓ You authorise an adviser through HMRC's online service or on form 64-8.

✓ A fixed fee suits defined work such as a tax return, residence review or disclosure.

✓ Promises of zero UK tax through structures HMRC will not notice are a red flag.

Choosing a UK tax adviser when you live abroad is not just about finding someone who can file a tax return. If you have left the UK with income still here, you are coming back after years overseas, or your money crosses borders, you need someone who works with these rules every day.

The wrong adviser can cost you thousands in missed reliefs, penalties for incorrect filings, or positions that attract HMRC's attention for the wrong reasons. The right one saves you money, protects your compliance record and gives you a clear answer on where you stand.

This guide explains what makes expat tax different, the checks to run before you engage anyone, what changed for tax advisers in 2026, and the red flags to walk away from.

If you would rather speak to one now, Global Tax Consulting is a UK expat tax advisor for people leaving, returning to or living outside the UK.

Why is expat tax harder than standard UK tax?

A standard return asks how much you earned. An expat return first has to answer where you are resident, which country gets to tax each type of income, and which reliefs and claims apply. Four areas cause most of the problems:

➜ The Statutory Residence Test: it is not a simple day count. Automatic tests, five UK ties and split-year cases can each change the answer. See our 📖 Statutory Residence Test 101.

➜ Double tax treaties: each of the UK's treaties is different. Applying the wrong article means paying tax twice or claiming relief you are not entitled to. See 📖 how UK double tax treaties work.

➜ The FIG regime: since April 2025, new arrivals who have not been UK resident for ten years can exempt foreign income and gains for four years, but the claim has a cost. See our guide to the 📖 4-year FIG regime.

➜ Non-resident property rules: selling UK property while living abroad needs a 60-day return, even when there is no tax to pay. See 📖 non-resident capital gains tax.

These rules interact. A residence conclusion drives the treaty position, which drives the forms, which drive the refund. That is why expat work needs a specialist rather than a general practice.

General accountant or expat specialist?

Most high-street accountants focus on domestic clients: small businesses, landlords and employees with UK-only income. They prepare standard returns efficiently, but rarely see residence reviews, treaty claims or FIG elections. When they do, they are often learning on your case.

Image 1: same tax return, different questions

This is an illustrative comparison of typical practice.

The gaps show up in predictable places. A missed 60-day property return. An overseas pension taxed in the UK when the treaty gave the taxing right elsewhere. A return filed without the SA109 residence pages, so the split year or treaty claim was never made.

A specialist works mainly with clients who have cross-border exposure, and keeps current on:

➜ Residence: the SRT, split-year cases for leavers and arrivers, and HMRC's guidance in RDR3.

➜ Treaties: how the tie-breaker and income articles work across many countries.

➜ Regime changes: the end of the remittance basis, the FIG regime and residence-based inheritance tax from April 2025.

➜ Both sides: how UK tax interacts with the tax in your other country, and when to bring in a local adviser.

Six checks before you engage an adviser

Run these six checks before you sign anything.

Image 2: six checks before you sign

1. Qualifications you can verify

"Tax adviser" is not a protected title in the UK, so anyone can use it. Look for membership of a professional body that sets exams, requires continuing training and runs a complaints process: the Chartered Institute of Taxation (CTA), the Association of Taxation Technicians (ATT), the ICAEW or ACCA. Check the member directory rather than taking a logo on a website at face value.

2. Registered with HMRC

What changed in 2026? Finance Act 2026 made it a legal requirement for anyone paid to deal with HMRC on a client's behalf to register with HMRC and meet minimum standards. Registration opened on 18 May 2026 and is being phased in, with the final stages running into early 2027.

An adviser who is not registered, or cannot be, will not be able to talk to HMRC for you. Ask whether they have an agent services account and are registered under the new rules. HMRC does not endorse individual firms, so registration is a minimum, not a recommendation.

👉 HMRC guidance: registering as a tax adviser with HMRC

👉 The law: Finance Act 2026, section 223 (unregistered tax advisers)

👉 GOV.UK: tax advisers to register with HMRC and meet minimum standards

3. Supervised and insured

Tax advisers must be supervised for anti-money laundering, either by their professional body or by HMRC. Expect identity checks when you sign up. They are a sign the firm is doing things properly, not bureaucracy for its own sake. Ask, too, whether the firm holds professional indemnity insurance.

4. A clear scope and a clear fee

Is the price for the whole job? Transparent pricing protects you from surprises. Hourly billing charges for every email and call, and you will not know the final cost until the work is done.

A fixed fee for a defined piece of work, such as a tax return, a residence review or a disclosure, gives you certainty and removes any incentive to take longer. Check the engagement letter says what is included: the SA109 residence pages, treaty claims, correspondence with HMRC and any foreign tax credit calculations.

5. Secure systems

You will be sharing bank statements, employment contracts and investment records. A good adviser gives you an encrypted portal for documents, electronic signature for authorisations, and a way to see where your work stands without chasing. Unencrypted email attachments and paper-only processes are warning signs for both security and speed.

6. Reputation and responsiveness

Client feedback reveals patterns a sales call will not. Read verified reviews on Google or Trustpilot for what they say about response times and clarity, not just the star rating. Responsiveness matters most in the weeks before a deadline.

How does authorising an adviser work?

What does your adviser need from you? For Self Assessment, you authorise them through HMRC's online service or, where that is not possible, on paper form 64-8. Once authorised, they can file returns, make claims and talk to HMRC about your position.

If you only want help with one specific issue, that is limited authorisation, and HMRC now needs a signed letter rather than a 64-8. Either way, you remain legally responsible for your own tax, and you must check your return before your adviser files it.

👉 HMRC guidance: authorising an agent (64-8)

Our guide to 📖 HMRC forms for expats covers the 64-8 and the other forms you are likely to meet.

Questions to ask on the first call

➜ How many clients do you have in my situation? Leaving, arriving, non-resident landlord or dual resident, the answer should come easily.

➜ Which country do you advise on? A UK adviser should say so, and tell you how they coordinate with your adviser in the other country.

➜ What is included in the fee? Get the scope in writing, including HMRC correspondence.

➜ Who will do the work? Find out whether a qualified person prepares or reviews your return.

➜ What do you need from me, and by when? A clear checklist and timetable is a good sign of a well-run practice.

Red flags

➜ Promises of zero UK tax: if an adviser offers to eliminate your UK liability through structures HMRC supposedly will not notice, that is non-compliance dressed up as planning. It ends in back tax, interest and penalties.

➜ No expat track record: if the first conversation shows few expat clients or no experience of your scenario, keep looking.

➜ Vague answers on registration or credentials: a professional will happily confirm their qualifications, supervision and HMRC registration.

➜ Slow, unclear communication: days to return a call and vague answers to simple questions rarely improve once you have signed.

How Global Tax Consulting meets these criteria

Global Tax Consulting was founded in April 2023 by Emma McDermott, ATT, who previously worked at Deloitte and has been a member of the Association of Taxation Technicians since 2020. You can read our 104 reviews on Trustpilot and 134 reviews on Google, as at October 2026.

Frequently asked questions

Do I need a specialist tax adviser if I live abroad?

Not always. If you only have UK income taxed under PAYE, you may not need one. If you have UK rental income, a pension, a property sale, a split year or income in two countries, a specialist is usually worth the fee because the residence and treaty claims drive how much you pay.

What qualifications should a UK tax adviser have?

Look for membership of a professional body such as the Chartered Institute of Taxation (CTA), the Association of Taxation Technicians (ATT), the ICAEW or ACCA. "Tax adviser" is not a protected title, so check the body's member directory.

Do tax advisers have to register with HMRC?

Yes. Under Finance Act 2026, anyone paid to interact with HMRC on a client's behalf must register with HMRC and meet minimum standards. Registration opened in May 2026 and is being phased in until early 2027.

How do I authorise an adviser to deal with HMRC?

Through HMRC's online authorisation service or, if that is not possible, on form 64-8. For help with a single issue, HMRC needs a signed letter of authority instead. You stay legally responsible for your own tax either way.

Is a fixed fee better than hourly billing?

For defined work such as a tax return, residence review or disclosure, a fixed fee gives you certainty and removes any incentive to take longer. Complex advisory projects can still suit an hourly or staged arrangement, agreed in writing.

Last reviewed on 22 October 2026 by Emma McDermott, ATT, founder of Global Tax Consulting, in line with the law in force at that date: Finance Act 2026, section 223, and the HMRC guidance cited above.