A limited company can be a legitimate structure for a doctor's business, but it is not a universal method of increasing take-home pay. The answer depends on the actual work, contractual relationship, available benefits, business costs and what happens to the money after it enters the company.
The wrong starting question is how to make every session fit a preferred tax structure. The better question is how each genuine engagement should be treated, followed by a comparison of the arrangements that are actually available.
This guide reflects official information reviewed on 18 October 2026. It is a decision framework, not personalised tax or legal advice, and it deliberately avoids applying a single take-home percentage to every doctor.
Separate four different arrangements
PAYE employment means the doctor is paid through an employer's payroll under the applicable employment arrangement. Direct sole-trader work, where genuinely self-employed, is a different structure. A personal limited company creates another entity through which suitable business work may be supplied.
An umbrella company is different again: it may employ the worker while receiving the assignment payment from an agency. It should not be confused with the doctor's own personal service company.
Write down the proposed payer, contractual parties and work relationship before comparing rates. A platform such as Lantum, a hospital bank or a direct booking tool may help arrange the work, but its brand does not settle the tax treatment.
IR35 is about the underlying engagement
HMRC explains that off-payroll rules concern services supplied through an intermediary where the worker would otherwise be an employee for tax purposes. They apply contract by contract, so a doctor's portfolio can contain different outcomes.
A company invoice, several clients or an agreement using the word locum does not by itself resolve the assessment. Consider the written terms and actual working practices together. Obtain advice rather than relying on a generic template said to guarantee a particular result.
Do not invent substitution arrangements, independence or business risk that do not exist in practice. A defensible structure reflects the real service. It is not a set of phrases added after the work has already been agreed.
Establish who must make the decision
For public-sector clients and medium or large private-sector clients, HMRC's current guidance places the status decision with the client. The doctor should receive the determination and reasons through the relevant process and can raise a disagreement where appropriate.
For a qualifying small private-sector client, the worker's intermediary generally retains responsibility for assessing the rules. Small-client status is therefore not the same as a conclusion that the engagement is outside IR35.
Ask for clarity about the actual end client and applicable process. Do not assume that the size of the recruitment platform or agency answers the question about the organisation receiving the service.
Compare an umbrella rate with the correct number
HMRC's umbrella-company guidance distinguishes the assignment rate paid to the umbrella from the worker's gross pay. The key information document and reconciliation should explain the relevant deductions and remuneration arrangement.
An advertised umbrella assignment rate should not be compared directly with a PAYE gross hourly rate. Ask for a worked pay illustration showing the assignment amount, operating costs, employer-related costs, gross pay, holiday treatment and deductions from gross pay.
Do not accept a verbal take-home promise without understanding the calculation. A higher figure at the top of a recruitment message can conceal a different basis of comparison rather than a better paid role.
Company receipts are not personal disposable income
Separate company turnover, allowable business costs, profits, tax liabilities and money paid to the owner. A balance in a business bank account is not a figure that can automatically be treated as personal spending money.
Consider an illustrative company receiving GBP40,000 from work and incurring GBP5,000 of genuine business costs. The remaining GBP35,000 is not a calculation of the doctor's final take-home income. Further treatment depends on the engagement, company position, extraction and the individual's wider circumstances.
Likewise, leaving money in the company is different from needing all the receipts immediately for living costs. Ask an accountant to compare the actual scenarios rather than presenting retained business funds as a tax-free personal salary.
Put the administrative cost into the model
A company can require accountancy, bookkeeping, payroll where applicable, statutory records and ongoing administration. Obtain current quotes for the actual service needed rather than assuming these costs are negligible.
Suppose an illustrative structure creates GBP2,000 of additional annual professional and administrative costs for GBP20,000 of relevant receipts. That is a 10% cost before analysing any tax difference. With a different scale or an existing business infrastructure, the incremental cost might be different.
This is not an estimate of standard accountancy fees. It demonstrates why the volume of work and the costs already incurred elsewhere in the business can affect the decision.
Do not omit NHS pension considerations
For ordinary GP locum work, the BMA states that earnings processed through a limited company cannot be pensioned in the NHS scheme under the locum arrangement described. That can materially change a comparison with otherwise eligible direct locum work.
Other pension planning is a separate question and should be assessed with appropriate advice. Do not treat every pension contribution as interchangeable or convert a published employer contribution percentage into immediately available cash.
Also review leave, sickness protection, development support and income stability under the alternatives. A tax-focused calculation that omits important benefits is not a complete measure of value.
A mixed clinical and non-clinical portfolio needs separate treatment
A doctor may have PAYE employment, locum contracts, private clinical work, writing and advisory income. Their similarity is medical expertise; their legal and tax treatment does not automatically match.
For VAT, HMRC's healthcare guidance makes the nature and purpose of a supply relevant. Do not assume that every report, advisory engagement or educational service is exempt because the supplier is medically qualified.
Keep records that identify each income stream and its contractual basis. For sole-trader activity, assess applicable Making Tax Digital requirements separately from company obligations. Buying a bookkeeping application does not itself settle either issue.
Use an adviser meeting to resolve specific decisions
Bring the actual contracts, status determinations, expected receipts, business costs, other income and pension arrangements. State whether you need the income personally now or intend to retain funds for genuine business purposes.
Ask the adviser to compare available structures using the same assumptions and to identify which facts would change the conclusion. Keep uncertain opportunities out of the base case. Review the answer when the portfolio changes rather than treating incorporation as a permanent financial solution.
iatroX's locum GP toolkit can help organise the wider administrative and clinical workflow. It does not replace regulated advice. The best structure is one that accurately reflects the work and remains worthwhile after all costs, benefits and responsibilities are included.
Related reading: comparing effective earnings across medical roles and the locum GP administration and learning toolkit.
FAQs
Does using a limited company automatically put locum work outside IR35?
No. The relevant rules assess the actual engagement, not simply the presence of a company or the wording of an invoice. Different contracts within the same portfolio can have different outcomes.
Is an umbrella assignment rate the same as gross pay?
No. HMRC distinguishes the payment to the umbrella from the worker's gross remuneration. Request the key information document and a clear reconciliation before comparing it with a PAYE offer.
Should every GP locum incorporate once earnings increase?
No universal threshold establishes that conclusion. Consider status, pension eligibility, costs, benefits, other income and extraction needs with an appropriately qualified adviser using the actual contracts.
Organise the wider work and administration through iatroX's locum GP toolkit.