You Don't Owe UK Tax on Everything After You Leave

Most agency founders I speak to assume that moving to Dubai halfway through the UK tax year means they pay UK tax on everything earned up to 5 April, then nothing from the day they land in the UAE. That is almost right, but the detail matters.

If you move on, say, 1 October 2025, you do not file a UK tax return for the full 2025/26 year and pay tax on all your worldwide income. HMRC uses something called split year treatment to divide the tax year into a UK part and a non-UK part. Only income arising in the UK part is taxable here. Income arising after you become non-resident is outside the UK tax net.

This is not automatic. You have to claim it on your tax return. And you have to meet one of several specific tests to qualify. Get it wrong and HMRC could treat you as UK resident for the whole year, meaning your Dubai income remains taxable in the UK.

Let's work through how split year treatment actually applies to an agency founder moving to Dubai mid-tax year.

When Do You Become Non-Resident?

The Statutory Residence Test (SRT) determines your UK residence status. You are non-resident for a tax year if you spend fewer than 16 days in the UK (or 46 days if you have not been UK resident for the previous three years) and you meet the "sufficient ties" test. But the key point for movers is this: you do not become non-resident on the day you fly. You become non-resident for the whole tax year if you meet the conditions. Split year treatment then carves out the period before you left as the UK part.

HMRC publishes a list of "split year cases" in HMRC6 (the residence manual). For a move to Dubai, you will typically rely on Case 1 or Case 4.

  • Case 1: You leave the UK to start full-time work abroad. You must have a period of at least one tax year during which you work full-time overseas and spend fewer than 91 days in the UK per year. The split happens on the day you leave.
  • Case 4: You start to have a home abroad. If you already have a home in the UK and acquire a home in Dubai, and spend more time in the Dubai home than the UK home in the relevant period, the split happens on the later of: the date you leave the UK, or the date the overseas home becomes available to you.

Most agency founders moving to Dubai will use Case 1 because they are going to run their business from the UAE. But if you are keeping a UK home and spending time in both places, Case 4 may be more appropriate.

What Happens to Your Agency Income?

Your agency income splits into two categories: UK source and non-UK source.

Income earned before you leave the UK is taxable here regardless. That includes:

  • Salary paid for work done while you were physically in the UK
  • Dividends declared by your UK company while you were UK resident
  • Profits from your UK agency that relate to the period before you left

Income earned after you become non-resident is outside UK tax, provided it is not UK source income. But here is where agency founders often trip up: dividends paid by a UK company are UK source income. Even if you are living in Dubai, dividends from your UK agency are taxable in the UK unless you are non-resident for the whole tax year and have no other UK income.

If you move mid-year and split year treatment applies, dividends paid after the split date are still UK source income. They remain within the UK tax net. The split year only changes your residence status for the non-UK part. It does not change the source of the income.

This is a critical distinction. Many founders assume that once they are non-resident, all income from their UK company is tax-free. It is not. Dividends from a UK company are always UK source income. The split year treatment means you only pay UK tax on the dividends that relate to the UK part of the year, but HMRC does not automatically apportion them. You have to do that yourself.

Practical Example

Let's say you run a 12-person digital agency billing £800k per year. You move to Dubai on 1 December 2025. Your company pays you a salary of £12,570 per year and dividends of £100,000 per year.

Under split year treatment (Case 1), the UK part runs from 6 April 2025 to 30 November 2025 (239 days). The non-UK part runs from 1 December 2025 to 5 April 2026 (126 days).

Your salary is time-apportioned: £12,570 x 239/365 = £8,230 is taxable in the UK. The remaining £4,340 is not taxable in the UK because it falls in the non-UK part.

Your dividends are trickier. HMRC says dividends are taxable in the year they are paid, not the year they are earned. If you pay yourself a dividend of £50,000 on 30 November and another £50,000 on 1 March, the November dividend is taxable in the UK part. The March dividend is also taxable in the UK because it is UK source income, even though you are non-resident when you receive it. The split year does not protect UK source income.

To avoid this, many agency founders restructure their dividend payments before leaving. They take all their dividends before the split date, or they use a holding company structure to route dividends through a non-UK entity. This is where proper planning matters.

What About Capital Gains?

Capital gains are treated differently. If you sell shares in your agency after you become non-resident, the gain is not taxable in the UK provided you remain non-resident for at least five full tax years. This is the five-year rule. If you return within five years, the gain becomes taxable in the year you return.

If you sell before you leave, the gain is taxable in the UK part of the split year. Business Asset Disposal Relief (BADR) may apply if you meet the conditions, but the rates have changed. From 6 April 2025, BADR is 14%. From 6 April 2026, it rises to 18%. If you are planning an exit around a Dubai move, the timing of the sale and the move needs careful coordination.

What Happens to Your UK Company?

Your UK company remains UK tax resident. It pays corporation tax on its profits regardless of where you live. The company's tax position does not change just because you move to Dubai. You still need to file annual accounts and a CT600 return.

What does change is your personal tax position. You stop being liable for UK National Insurance on your salary after you leave. Your company stops paying employer NI on your salary from the split date. But the company still needs to operate payroll for any UK employees you leave behind.

Many agency founders keep their UK company running while they manage it from Dubai. This is fine. The company's management and control is where the board meets and makes decisions. If you are the sole director and you are in Dubai, the company's management and control may shift to Dubai, which could affect its tax residence. This is a complex area. You should speak to an accountant who understands both UK and UAE tax before you move.

What About Your Personal Tax Return?

You still file a UK tax return for the year you move. On that return, you claim split year treatment. You complete the residence pages (SA109) to show your non-resident status for part of the year. You then report only the income that falls in the UK part.

HMRC will check your claim. They look for evidence that you genuinely left the UK and established a home abroad. That means:

  • Proof of your Dubai residence visa
  • Tenancy agreement or property purchase in Dubai
  • Bank statements showing UAE transactions
  • Flight records showing time spent in the UK
  • Employment contract or evidence of work carried out in the UAE

Keep these records for at least six years. HMRC can open an enquiry into your return up to 12 months after filing, and if they suspect non-compliance, they can go back further.

Common Mistakes Agency Founders Make

Mistake 1: Assuming split year treatment is automatic. It is not. You must claim it on your tax return. If you do not, HMRC treats you as UK resident for the whole year.

Mistake 2: Paying dividends after you leave. As we covered, dividends from a UK company remain UK source income. They are taxable in the UK regardless of your residence status. Plan your dividend payments before you move.

Mistake 3: Keeping a UK home. If you keep a UK home and spend more than 16 days there per year, HMRC may argue you are still UK resident. The split year treatment only works if you genuinely break your UK ties. Selling or renting out your UK home strengthens your case.

Mistake 4: Ignoring the five-year rule on capital gains. If you sell shares in your agency within five years of returning to the UK, the gain becomes taxable. If you are planning to return, think carefully about the timing of any exit.

Mistake 5: Not getting professional advice. The split year rules are detailed and fact-specific. A mistake can cost you tens of thousands in unexpected tax. Speak to an ICAEW qualified accountant who works with agency founders before you book the flight.

What Should You Do Before You Move?

Here is a practical checklist for agency founders moving to Dubai mid-tax year:

  • Confirm your split year case. Are you Case 1 (full-time work abroad) or Case 4 (home abroad)? This determines the split date.
  • Plan your dividend payments. Take all dividends before the split date, or structure them through a holding company.
  • Review your UK home. Sell it or rent it out. Keeping it weakens your non-residence claim.
  • Set up your Dubai bank account and visa. HMRC wants evidence of genuine relocation.
  • Update your company's registered address and director details. This is not strictly necessary for tax purposes, but it supports your story.
  • File your UK tax return for the year of move. Claim split year treatment on the SA109.
  • Keep records. Flight bookings, tenancy agreements, bank statements, employment contracts. Everything.

If your contractor mix has changed in the last 12 months, or if you are planning to sell shares in your agency around the same time as the move, ask your accountant before year-end. The interaction between IR35, capital gains, and split year treatment can create unexpected liabilities if you do not plan ahead.

Moving to Dubai mid-tax year is a significant financial decision. The split year rules are designed to be fair, but they require careful application. Get the structure right and you can save a substantial amount in UK tax. Get it wrong and you could end up paying tax on income you thought was protected.

Our team at Agency Founder Finance specialises in helping agency founders navigate these transitions. We are ICAEW qualified accountants who understand both UK and UAE tax. If you are planning a move, we can help you structure it properly.