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US citizens in the UK · Tax basics

The US-UK tax treaty and the saving clause

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The treaty stops most double taxation, but the saving clause lets the US tax its citizens almost as if it were not there. What survives the clause is a short, specific list, and its two pension paragraphs are the most useful things on it for someone saving here.

The US-UK double taxation treaty divides up taxing rights between the two countries so the same income is not fully taxed twice. For most people it works quietly in the background: you pay UK tax where the UK has first claim, and credit it against any US tax on the same income.

The saving clause

The catch is a provision called the saving clause. It lets the United States tax its citizens and green-card holders as though the treaty did not exist, overriding most of the relief the treaty otherwise gives. Because US tax is based on citizenship, an American in the UK stays inside the US net, and the saving clause is what keeps them there.

What survives the clause

The exceptions are set out in Article 1(5), as rewritten by the 2002 protocol. For a US citizen living in the UK, the ones that matter are these.

  • Contributions to a workplace pension. Article 18(5) relieves contributions to a UK scheme made through a UK employer, and keeps employer contributions and accrued benefits off US income, up to what a comparable US plan would allow.
  • Growth inside a pension. Article 18(1) lets a pension scheme's income be taxed as yours only when it is paid out. Its wording covers a scheme in the other country from the one you live in, but the US Treasury's technical explanation says a US citizen resident in the UK will not be taxed by the US on the earnings and accretions of a UK pension fund.
  • US social security, child support and alimony. The technical explanation says a US citizen resident in the UK will not be subject to US tax on any of them.
  • The treaty's own machinery: its article on relief from double taxation, non-discrimination and the mutual agreement procedure.

Just as telling is what is missing. A lump sum from a pension is not on the list, and HMRC's own treaty manual concludes that the US can tax lump sums received by US citizens from UK schemes. The rules for government service, students and teachers survive only for people who are neither US citizens nor green card holders. Read the list literally rather than assuming the treaty protects more than it does.

The foreign tax credit and exclusion

Outside the treaty, two mechanisms do most of the work of preventing double tax for Americans abroad. The foreign tax credit, claimed on Form 1116, credits the UK tax you paid against the US tax due on the same income; only income, war profits and excess profits taxes qualify. The foreign earned income exclusion, claimed on Form 2555, instead takes earned income off the return altogether, up to $130,000 for 2025 and $132,900 for 2026. UK rates are often high enough that the credit wipes out the US bill on the same income, but the US return still has to be filed to claim it. See filing a US return from the UK for the thresholds, the deadline abroad and what each mechanism asks of you.

How the two pension paragraphs apply is covered in how the US taxes your UK workplace pension and how the US taxes your UK SIPP.

Sources

Common questions

Does the US-UK treaty stop me being taxed twice?

Mostly, but not by itself if you are a US citizen. The treaty divides taxing rights so the same income is not fully taxed twice, and for most people it works quietly in the background. For Americans the heavy lifting is usually done by the foreign tax credit and the foreign earned income exclusion instead, because the saving clause overrides most treaty relief for US citizens.

What is the saving clause?

A provision that lets the United States tax its citizens and green-card holders as though the treaty did not exist, overriding most of the relief the treaty otherwise gives. Because US tax is based on citizenship, an American in the UK stays inside the US net, and the saving clause is what keeps them there.

What survives the saving clause?

A short list in Article 1(5), as rewritten by the 2002 protocol. For a US citizen in the UK the useful items are the two pension paragraphs: Article 18(5) relieves workplace pension contributions made through a UK employer, and Article 18(1), on the US Treasury's reading, keeps growth in a UK pension untaxed by the US until it is paid out. US social security, child support and alimony also survive. A pension lump sum does not, and the rules for government service, students and teachers survive only for people who are not US citizens or green card holders.

Confirm your own position with a cross-border specialist. Acceptance policies and tax rules change, and your facts may differ from the general case. Rates and terms here are the provider's published figures rather than an offer, and the provider decides each application on its own criteria. Use this as a map, not a ruling. Last checked .
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