Double tax treaties: how relief works

When you hold financial interests across borders, one of the most significant concerns is double taxation. This happens when two countries each claim the right to tax the same income or capital gain. To manage that, the UK has an extensive network of double tax treaties, which are international agreements designed to make sure taxpayers are not unfairly burdened by overlapping jurisdictions.

At its core a treaty is a piece of international tax law aimed at reducing the friction of cross-border activity. Whether you are a digital nomad, an expat working abroad, or an investor with assets in several territories, understanding how these agreements work is essential. They provide the framework for deciding which country has the primary taxing rights, and how relief is given where both have a claim.

When does double taxation occur?

It typically arises in two situations. The first is dual residence, where you are treated as tax resident in two countries at once under their respective domestic rules. You might meet the UK Statutory Residence Test while also being resident in another country where you spend significant time. In that case both may seek to tax your worldwide income.

The second is where you are resident in one country but receive income sourced in another. Without a treaty, the source country may apply withholding tax at the point of origin while your home country taxes the same income as part of your global earnings.

Mechanisms for tax relief

Treaties set out exactly how double taxation is relieved. Relief generally comes through one of three mechanisms, depending on the type of income involved.

Image 1 — the three relief mechanisms

●       Exclusive taxing rights.  The treaty gives only one country the right to tax the income, and the other must exempt it entirely. A common example is private pension income, which is frequently taxable only where the recipient lives.

●       Limited taxing rights.  For certain passive income, such as dividends or interest, the source country may tax it but only up to a set percentage, often 5%, 10% or 15%. The residence country then taxes it and accounts for the tax already paid.

●       Tax credit relief.  The most common method. Both countries may tax the income, but the country of residence must give a credit for the tax paid in the source country, so your total does not exceed the higher of the two rates.

Applying these rules correctly is what prevents the unnecessary loss of wealth to duplicated tax charges.

Typical treaty positions

Every treaty is different, but most UK agreements follow the OECD Model Tax Convention. To read your position you need to distinguish the residence country, where you live, from the source country, where the money is generated.

Image 2 — typical positions by income type

●       Bank interest.  In most UK treaties, interest is taxable only where you are resident. Where the administrative steps are followed correctly, the source country should not withhold tax on the payments.

●       Dividends.  Often taxable in both. The source country is usually restricted to a maximum percentage. Under the UK-US treaty, for example, US dividend income is typically subject to 15% withholding at source, which you then claim as a credit on your UK return.

●       Rental income.  Income from immovable property is taxable in the country where the property sits, and generally also in your country of residence, which gives credit for the foreign tax paid.

●       Employment income.  Generally taxable where you are resident. However, where you physically perform workdays in another country, that country may also tax the portion of your salary relating to those days.

●       Private pensions.  Most modern UK treaties give the sole right of taxation to the country of residence, which simplifies matters considerably for retirees abroad.

●       Government pensions.  Pensions paid by a government for services rendered, such as teaching, civil service or military, are usually taxable only in the country paying the pension.

One important exception to the employment position is worth knowing. Many treaties exempt short-term working visits from tax in the country where the duties are performed, provided you are there for fewer than 183 days, your employer is not resident there, and the cost is not borne by a permanent establishment in that country. All three conditions must be met.

🌎 UKs network of double taxation agreements

Real world examples

Scenario A: the UK and Spain

If you are Spanish resident receiving a UK private pension, the UK-Spain treaty typically provides that the income is taxable only in Spain. You can therefore apply for the pension to be paid gross from the UK.

🇪🇸 UK-Spain double taxation agreement

Scenario B: the UK and Germany

A UK resident receiving dividend income from a German company will find the income taxable in both countries. Under the treaty Germany may tax the dividend at up to 15%. On the UK return, the individual reports the full dividend and credits the German tax against the UK liability, which prevents double taxation.

🇩🇪 UK-German double taxation agreement

Scenario C: the UK and Australia

An Australian resident who owns rental property in the UK is taxable in both jurisdictions. The UK, as the source country, has the primary right to tax the rental profits. Australia, as the residence country, also taxes the income but gives a foreign tax credit for the amount paid to HMRC.

🇦🇺 UK-Australia double taxation agreement

Relief is not automatic

This is the point that most often catches people out. A treaty does not apply itself. Relief has to be claimed, and usually evidenced.

Depending on the position, that may mean claiming foreign tax credit relief on your self assessment return, obtaining a certificate of residence from the country you are resident in, or submitting a form to the overseas tax authority so that withholding is reduced at source rather than reclaimed afterwards.