Start with the payslip, because it is the simple part. An NHS doctor on a salaried contract pays tax through PAYE, and credits usually cover whatever America asks for. Nothing about that arrangement causes trouble.
The trouble starts with the private list. Fees earned outside the salaried post reach an American return by a different route, and that route carries a charge the usual reliefs do not touch.
So the year splits into four streams rather than one. In our practice, three of them are neutral and one of them is expensive, and the expensive one is not the one people ask about.
What is the problem for an NHS doctor?
Private practice, in a word. Fees outside the salaried post are self-employment for American purposes. Self-employment brings a social security charge, and the foreign earned income exclusion does nothing about it.
Where private practice actually costs money
In social security rather than income tax. Private practice is self-employment for American purposes, and the IRS is explicit that you count all self-employment income when figuring net earnings, even where the foreign earned income exclusion removed it from income tax.
So a consultant can owe nothing in US income tax and still face a bill on the practice profit.
The fix is the social security agreement rather than the treaty. A certificate of coverage showing the earnings sit in the UK system removes that line, and the IRS explains the framework behind these agreements.
Our article on the US-UK totalisation agreement covers how to obtain one.
Why does the treaty not fix it?
Because the tax treaty covers income taxes, and this is not one. Social security charges answer to a separate agreement between the two countries, with its own tests and its own paperwork. Reading the treaty for an answer here is reading the wrong document.
That distinction explains most of the confusion we see. An NHS doctor can be fully protected on income tax and completely exposed on the other charge.
So ask which instrument applies before asking what it says. The answer is usually the social security agreement.
How do you remove the charge?
With a certificate of coverage. You apply to HMRC, which confirms that your earnings already sit inside the British system. That certificate is what supports leaving the American charge off the return, and it takes weeks rather than months.
Keep it with the tax papers rather than in an inbox. It is the only document that proves the position.
Apply once your private work begins, not once the return is due. Our clients who leave it late usually file an extension while they wait.
Do locum shifts change the answer?
They can, and the first question is always the nature of the engagement rather than the rate. Work through an agency on a payroll is employment. Invoicing a trust directly through your own company is not, and the middle ground is where disputes live.
The British side has its own rules on off-payroll working, which decide who operates payroll.
For US purposes, the label follows the substance. Employment brings one set of consequences and self-employment another, including the social security point above.
Should a consultant use a limited company?
Many do for private work, and it changes the American position considerably. A UK company owned by a US person is a controlled foreign corporation, which brings information reporting and possibly current taxation of its profits.
Form 5471 is the reporting vehicle, and the calculations behind it are not trivial.
Our article on a US person with a UK limited company sets out what that involves before you incorporate rather than after.
Does the US tax NHS pension growth each year?
Not where Article 18(1) applies. The treaty provides that income earned by a pension scheme may be taxed as the individual's income only when it is paid to them, rather than as it accrues inside the scheme.
That is precisely what a defined benefit scheme needs, since nothing is distributed for decades.
Better still, Article 18(1) sits in the part of the saving clause exceptions preserved for everyone, citizens included. So an American consultant can rely on it rather than merely hope.
How do you know the scheme qualifies?
By reading the definition rather than the brochure. The treaty describes a pension scheme as any plan, scheme, fund, trust or other arrangement established in a country, generally exempt from income taxation there, and operated principally to administer or provide pension or retirement benefits.
A UK registered pension scheme generally meets that description. A non-registered arrangement or an unusual employer top-up may not.
We check the specific scheme rather than assuming, because the answer changes the whole return. Our article on UK pensions under US rules covers the wider position.
| Income source | UK treatment | US treatment | Where the cost lands |
|---|---|---|---|
| Salaried NHS post | PAYE | Reportable, credit or exclusion available | Usually neutral |
| NHS pension accrual | No charge until drawn | Deferred under Article 18(1) | Neutral while it accrues |
| Employee pension contributions | Relief at source | Relief under Article 18(5) conditions | Usually neutral |
| Private practice fees | Self Assessment, Class 2 and 4 | Self-employment tax unless the agreement applies | Real cost if unclaimed |
| Locum work through an agency | Depends on the engagement | Employment or self-employment | Depends on the facts |
| Annual allowance charge | UK tax charge | No matching US relief | Real cost, needs modelling |
What about the annual allowance?
It bites hardest on exactly this group. Defined benefit accrual counts towards the pension annual allowance, and a promotion or a pay rise can produce a charge in a year when nothing was paid to you at all.
America gives no relief for that charge, because it relates to a pension the US is not currently taxing.
That asymmetry is worth modelling before choosing whether to remain in the scheme. The decision is rarely a pure pension question for someone filing in two countries.
Drawing the NHS pension later
The deferral under Article 18(1) ends when payments begin, and a different paragraph governs what happens then. Periodic pension payments and lump sums are treated differently under Article 17, and the lump sum rule in particular surprises people.
Plan the drawing decision years ahead if you can. The order in which you take benefits affects both returns.
Our note on 401(k) withdrawals as a UK resident covers the mirror-image question for American plans.
What about the tax-free lump sum?
Britain permits a tax-free element within limits. America does not automatically follow that treatment, and the treaty paragraph dealing with lump sums allocates the taxing right rather than granting an exemption.
So a payment that is tax free here can still be taxable there. That is a planning question rather than a surprise, provided it is asked in advance.
We look at it alongside the rest of the retirement position, because the lump sum is rarely the only decision being made that year.
Does an NHS doctor need to file at all?
Yes, on the same basis as any other citizen abroad. A US passport brings a filing duty wherever you work, and a consultant's income sits well above every threshold. So the question is never whether to file but which reliefs to claim.
Two routes exist for the salary. The exclusion removes foreign pay up to a cap, while the credit offsets American tax with the British tax you already paid.
For most doctors the credit does more, because UK rates on a consultant's salary are high. We model both each year rather than repeating last year's choice.
Training grades and the early years
A junior NHS doctor has a simpler picture and one recurring problem. Rotations move you between trusts, so payslips arrive from several employers in a single year and the paperwork scatters.
Collect the P45 from each move as it happens. Reconstructing a training year from memory is far harder than a consultant year.
Pension accrual starts immediately, which is worth knowing early. The treaty position on it is the same at every grade.
Working abroad, or returning to America
Plenty of doctors move again, and each move resets the analysis. A fellowship in the United States turns British income into foreign income on a US return and ends the UK residence position at some point in the year.
Two things need checking before you fly. Whether the certificate of coverage still describes your work, and what happens to the pension you are leaving behind.
An NHS doctor who leaves mid-year usually has a split year in Britain and a full year in America. Those do not line up, and the reconciliation needs the dates.
We plan that year in advance where we can, because the choices narrow once the payroll has closed.
What paperwork should an NHS doctor keep?
Five things, and none of them take long. Your payslips and P60, your annual scheme statement, your practice accounts, the certificate of coverage, and a note of any annual allowance charge.
Those five answer every question either tax authority asks. Sorted by year, they also make each return faster to prepare.
In our practice, doctors are the group most likely to have all five and least likely to have them in one place.
Getting a consultant's position straight, step by step
This sequence takes an hour and settles most of the year.
- Separate your income into salaried employment, pension accrual, private practice and locum work.
- Confirm the pension scheme meets the treaty definition, and record why.
- Check whether a certificate of coverage covers your self-employed earnings.
- Estimate any annual allowance charge early, since it affects both returns.
- Decide whether private work runs personally or through a company, with the American reporting in mind.
- Match UK tax paid to the income it relates to, for credit purposes.
- Keep the scheme statements, the practice accounts and the certificate together.
An illustrative example
Take an illustrative year. An American consultant earns £110,000 from a salaried NHS post and £45,000 from private practice, while accruing pension benefits in the usual way.
The salary and the accrual cause little difficulty: credits cover the income tax, and Article 18(1) defers the pension growth. The private practice profit is the problem, because self-employment tax applies to it unless the social security agreement says otherwise.
With a certificate, that line disappears. Without one, it is a five-figure charge on income that produced no US income tax at all. The figures are illustrative; the shape is the one we see most.
Common mistakes we see
First, assuming the tax treaty covers social security charges. It does not, and a separate agreement does.
Second, treating the exclusion as protection against self-employment tax. Third, incorporating for private work without looking at the American consequences.
Fourth, ignoring an annual allowance charge until the scheme statement arrives. Our clients who model it in advance make better decisions about staying in the scheme.
Fifth, assuming a hospital payroll department can answer any of this. They operate PAYE correctly and have no view on an American return, which is a different filing in a different currency.
How US UK Tax Hub helps an NHS doctor
We separate the four income streams, confirm the pension's treaty status in writing, and get the certificate of coverage in place before the return rather than after it. That sequence removes the largest avoidable cost in this group.
Our treaty relief service covers the pension analysis and the disclosures, and we prepare both returns so the figures agree.
Send us a payslip, a scheme statement and your practice accounts, and we will tell you where the exposure sits.
