Medical professionals in the UK are, statistically, among the highest earners — and yet many are surprised to discover just how exposed they can be when it comes to tax. NHS employment gives a false sense of security: PAYE handles most of it, so the complexity only becomes visible when something changes. A locum shift here, a private clinic session there, a pension statement that suddenly shows a six-figure tax charge — and suddenly the picture looks very different.

According to NHS workforce data published in late 2025, there are now over 1.5 million people working across the NHS. Research consistently highlights that pay, stress, and financial uncertainty are among the leading factors pushing experienced doctors to consider locum or private work. When they do make that move — even partially — the tax implications can be significant and are frequently misunderstood.

This post covers the areas we see come up most often when working with doctors and other healthcare professionals: self-assessment, the locum tax position, the limited company question, and the NHS pension annual allowance charge.

Most NHS consultants and GPs assume that because they are employed, HMRC is taking care of their tax. For many, that is broadly true — until it isn’t. The trigger points that push medical professionals into self-assessment territory include:

• Locum or sessional work outside the main NHS role
• Income from private practice, medico-legal work, or clinical research
• Earnings above £100,000, which affects the personal allowance
• The high income child benefit charge if household income exceeds £60,000
• Rental income or other investment income

Once any of these apply, you are legally required to register for self-assessment and file a tax return. The deadlines and penalties are the same for a doctor as they are for anyone else — there is no leniency for a busy rota.

What makes this particularly tricky is that many doctors only realise they needed to file a return after HMRC writes to them — sometimes years later, with interest and penalties added. We see this pattern regularly. The fix is straightforward once you are set up, but the administrative backlog of sorting out multiple missed years is genuinely stressful and avoidable.

If you have any income outside PAYE — even a single locum shift — it is worth confirming your self-assessment status sooner rather than later.

Locum medicine sits in a particularly nuanced part of the tax landscape. Whether a locum doctor is treated as employed or self-employed for tax purposes depends on the specific engagement — not on a blanket rule or what the agency tells you.

HMRC applies IR35 and off-payroll working rules to locum arrangements, particularly where work is provided through a personal service company (PSC). Since the public sector off-payroll reforms came into effect, NHS trusts and GP federations acting as engagers are responsible for determining the employment status of locums they engage via intermediaries. In practice, many NHS bodies issue blanket inside-IR35 determinations, which means the locum is taxed as if they were an employee — even if they operate through their own limited company.

For locums working directly (not through a company), the self-employment question hinges on the usual HMRC tests: control, substitution, and mutuality of obligation. Casual locum shifts, where the doctor can accept or decline work and has no guarantee of continuity, often qualify as self-employment — but this is not automatic.

The practical implication is that locum income needs to be tracked carefully, the right NICs category applied, and any expenses claimed correctly. Allowable expenses for self-employed locums can include professional subscriptions (such as GMC registration fees and medical defence), CPD costs, equipment, and a proportion of travel — but only where those expenses are wholly and exclusively incurred in the course of the work.

This is the question we are asked most often by medical professionals considering private work. The short answer is: it depends on the IR35 position, the volume of private income, and your longer-term plans — but for many doctors, the tax efficiency argument for a limited company is weaker than it used to be.

Here is the core issue. If a significant portion of your work falls inside IR35 — as is common for locums working with NHS bodies — then income drawn through a personal service company will be taxed at broadly the same rate as employment income. The administrative overhead of running a company in that situation often outweighs the benefit.

Where a limited company can still make sense is for doctors with a genuine private practice client base, medico-legal fee income, or other commercial activities that sit clearly outside IR35. In those cases, the ability to retain profits within the company, pay a salary and dividends, and make pension contributions through the business can create meaningful tax advantages.

The decision should never be made based on what a colleague has done or on a general sense that companies are more tax efficient. It needs to be modelled properly — taking into account your specific income mix, the IR35 risk, your personal circumstances, and your pension position. We do this regularly for healthcare professionals and the answer is genuinely different case by case.

Perhaps the single most significant tax issue facing senior NHS doctors is the pension annual allowance charge. This catches many consultants and GPs completely off guard — often at exactly the point in their careers when they are most financially stretched.

The annual allowance limits the amount by which pension savings can grow in a tax year without triggering a tax charge. For the 2025/26 tax year, the standard annual allowance is £60,000. However, higher earners are subject to the tapered annual allowance, which can reduce this significantly — in the most extreme cases, to £10,000 for those with adjusted income above £360,000.

The NHS pension scheme is a defined benefit scheme, meaning the annual allowance is calculated on the notional growth in the pension — not on contributions made. In years where a doctor receives a significant pay rise, works additional sessions, or moves through a threshold in the scheme, the deemed growth can comfortably exceed the annual allowance, generating a tax charge that must be paid personally.

The good news is that there are legitimate options: scheme pays elections (where the pension scheme pays the charge and reduces the eventual pension), carry forward of unused allowance from previous years, and careful management of additional income. GMC revalidation requirements and the annual appraisal cycle also have indirect financial implications that are worth understanding as part of a broader financial plan. The key is identifying the exposure before the tax return deadline, not discovering it afterwards.

Working with medical professionals has taught us that the issues above are rarely isolated. A consultant with a growing private practice, locum income on the side, and an NHS pension they have not reviewed in years is carrying several layers of tax complexity simultaneously. Trying to address each one in isolation — or worse, leaving them all until January — is how unexpected bills happen.

Our practical recommendations for doctors who want to get on top of their finances:

• Register for self-assessment promptly if you have any non-PAYE income. Do not wait for HMRC to prompt you.
• Track your income across all sources — NHS, locum, private, investment — so you can see the full picture in real time, not just at year-end.
• Review your pension position annually, ideally before the end of the tax year, so you can use carry forward allowances and avoid surprise charges.
• Model the limited company question carefully before incorporating. The tax saving needs to justify the administrative cost and IR35 risk.
• Claim all legitimate expenses — GMC fees, medical defence, CPD, professional subscriptions, and relevant equipment are all potentially deductible in the right circumstances.

None of this requires a highly complex structure or aggressive tax planning. In most cases, the biggest gains come simply from getting the basics right, early and consistently.