Most locum pharmacists file a Self Assessment return as sole traders each year. The return is straightforward in structure, but the expenses question is where errors occur: over-claiming, under-claiming, or claiming on the assumption that self-employed status is a given when HMRC's own guidance says otherwise. This article covers the pharmacist-specific allowable expenses, the travel rules, and the two compliance changes (cash basis and MTD) that affect how locum income and costs are recorded.
One important framing note before the expenses: the question of which expenses you can claim only arises if the self-employed status holds. HMRC has a locum-pharmacist-specific page, ESM4270, and its position is more cautious than the generic contractor default. The full status question (control, substitution, financial risk, IR35) is covered in the companion post are locum pharmacists self-employed. This post assumes the status position has been considered and focuses on what happens next: which costs are claimable, how to record them, and what the MTD rules mean for your filing.
For operating structure (sole trader vs limited company vs umbrella), see the companion post on locum pharmacist limited company vs umbrella. To model take-home under different structures and income levels, the locum take-home comparator runs the numbers as a scenario tool (it states its simplifications and is not a filing-ready tax calculation).
What a locum pharmacist can claim, in short
A genuinely self-employed locum pharmacist can claim expenses that are wholly and exclusively incurred for the purpose of the trade. The pharmacist-specific set is: GPhC annual retention fees, professional indemnity insurance, CPD and revalidation costs, recognised professional body subscriptions, and qualifying travel between locum sites. Equipment and other costs may qualify if they meet the wholly-and-exclusively test and are not dual-purpose. The claim does not arise, however, if the self-employed status is not secure: as ESM4270 makes clear, HMRC's position on locum pharmacists is restrictive, and market convention is not a defence.
First: does self-employed status hold?
The expenses below only reduce your tax bill if the self-employed position is correct. Expenses claimed on a Self Assessment return that HMRC later reclassifies as employment income do not simply move: the unpaid income tax, Class 1 National Insurance (at higher employee and employer rates than self-employed Class 4), interest, and potential penalties all follow.
ESM4270 is HMRC's locum-pharmacist-specific page in the Employment Status Manual. It names the profession and sets out the circumstances in which rota-based locum arrangements may point toward employment rather than self-employment. Status is not decided by the label on the invoice or by what the agency or pharmacy calls the arrangement. It is decided on the facts of each engagement: who controls the work, whether a real right of substitution exists, and whether there is genuine financial risk on the engagement.
"Everyone does it self-employed" is not a defence. The companion article are locum pharmacists self-employed applies the three tests to a pharmacist's working pattern in detail. Read that first if the status position has not been reviewed recently.
Pharmacist-specific allowable expenses
The following table covers the expense items most relevant to a self-employed locum pharmacist. It is not a generic sole-trader checklist: every line is anchored on what a pharmacist actually spends to take locum bookings and maintain the right to practise.
| Expense | Allowable? | Pharmacist-specific note | Wholly-and-exclusively caveat |
|---|---|---|---|
| GPhC annual retention fee | Yes | Registration is the prerequisite to working as a pharmacist at all; the fee is incurred wholly for the trade. The 2026/27 fee is set by the General Pharmaceutical Council. | No personal element; the fee is professional registration, not optional membership. |
| Professional indemnity insurance | Yes | Cover required to accept locum bookings; a direct cost of trading. Confirm the policy covers locum practice specifically (some employer-arranged cover does not extend to freelance work). | No personal element if the policy covers only professional locum practice. |
| CPD and revalidation costs | Yes (with care) | GPhC requires continuing professional development as a condition of revalidation. Course fees and assessment costs directly required to maintain registration are allowable. Broader educational costs that go beyond maintaining existing knowledge may not qualify. | Must relate to existing skills and registration requirements, not acquisition of a new qualification. A course that qualifies you for a different role or career is not allowable. |
| Professional subscriptions and memberships | Yes, if HMRC-approved | Subscriptions to professional bodies on HMRC's approved list are allowable (for example the Royal Pharmaceutical Society). Subscriptions to bodies not on the approved list require the wholly-and-exclusively test to be met independently. | Non-professional memberships (clubs, social groups) are not allowable regardless of the profession. |
| Dispensing and clinical consumables | Only if you supply them | In most locum arrangements, the pharmacy provides all dispensing materials. If you supply your own (for example, a Responsible Pharmacist record book, pharmacy bag or counting tray), the cost is allowable as wholly for the trade. | Do not claim consumables provided by the pharmacy; they are not your expense. |
| Mobile phone (business proportion) | Business proportion only | A phone used to manage bookings, communicate with agencies and pharmacies, and run locum-related apps has a business element. If the phone is also personal, only the identifiable business proportion of the cost is allowable. | Dual-purpose cost: keep records of business vs personal use. A phone used exclusively for locum work is fully allowable; one shared with personal use requires apportionment. |
| Home office (proportion) | Limited application | If you have a room used exclusively for managing locum bookings, accounts and CPD (not a living room with a laptop on the sofa), a proportion of household costs may be allowable. HMRC's simplified flat-rate option for home working is available to sole traders. In practice, most locum pharmacists do not have a dedicated room, and the generic home-office claim is one of the most-scrutinised areas in sole-trader returns. | Exclusive use rule applies. The room must be used exclusively and regularly for the business for a property proportion claim. The flat-rate option avoids the exclusive-use test but is set at fixed weekly amounts. |
The unifying rule for every line in the table is the wholly-and-exclusively test set out in HMRC's guidance on expenses if you're self-employed: the cost must be incurred wholly and exclusively for the purposes of the trade. A cost that has an identifiable personal element is either disallowed in full (if it cannot be separated) or allowed only in its business proportion (if the two uses can be clearly distinguished).
Travel and the commuting trap
Travel is the expense that generates the most errors on locum Self Assessment returns, and the pharmacist-specific facts make it genuinely more nuanced than the generic rule.
The principle is this: travel between different locum sites in the course of your working day, or travel to a site that is not a regular base, is qualifying business travel. Travel from home to a place you attend regularly as a base (a pharmacy you cover every Tuesday, for example) is ordinary commuting, and commuting costs are not allowable for any taxpayer, employed or self-employed.
For a locum pharmacist, the test HMRC applies is whether the workplace is a "temporary" or "permanent" one. A workplace is temporary if attendance is for a limited duration or for a temporary purpose. A pharmacy you cover ad hoc across the year, at varying frequencies, with no pattern of regularity, is more likely to be a temporary workplace. A pharmacy you attend predictably on set days each week, with bookings that extend over a long period, starts to look more like a regular base, and the travel to it starts to look more like commuting.
Key points for locum pharmacists:
- Multiple sites on one day. Travel between pharmacy A in the morning and pharmacy B in the afternoon is travel between workplaces and is allowable in full. Travel from home to pharmacy A, and from pharmacy B back home, is ordinary commuting from and to the base of operations and is not allowable.
- A single site attended on varied but regular days. If you cover the same pharmacy most weeks for an extended period, HMRC may treat it as a permanent workplace. The travel to it is not then a deductible business expense.
- Overnight stays. If a locum booking requires an overnight stay away from your normal work area, the accommodation and subsistence costs for that trip may be claimable as business travel. The cost must be reasonable and wholly business-related.
- Mileage rates for cars. Where you use your own car, the approved mileage allowance is 55p per mile for the first 10,000 business miles in 2026/27, and 25p per mile above that. Keep a contemporaneous mileage log (date, start point, end point, purpose, miles). A log reconstructed at year-end from memory is not a strong basis for the claim.
- Public transport. Rail, bus and underground fares for qualifying business journeys are claimable at actual cost. Keep tickets or booking confirmations.
The short version: if you are travelling between different pharmacies in the course of your work, record it and claim it. If you are travelling to the same pharmacy you always cover, seek advice before claiming it as a business expense.
Cash basis: the default for sole-trader locums
Cash basis is the default recording method for unincorporated businesses, including sole-trader locum pharmacists. Under cash basis, income is recognised when money is received and expenses are recognised when they are paid. You do not accrue income earned but not yet invoiced, and you do not accrue costs incurred but not yet settled.
For most sole-trader locums, cash basis is the simpler and more natural method. Locum income is typically paid promptly (agencies settle within 30 days; direct pharmacy arrangements vary), and the main expenses are paid as incurred (the GPhC fee when billed, indemnity premiums when due, CPD courses when booked). There is rarely a large mismatch between invoicing and receipt that would make accruals accounting necessary.
Cash basis has some practical consequences worth noting:
- Stock and assets. Under cash basis, most asset purchases are deducted when paid (within the annual investment allowance limits), rather than being capitalised and written down over time. For most locums, who hold minimal assets, this rarely creates a difference.
- Opting out. You can elect to use traditional accruals accounting if cash basis does not suit your circumstances. Electing out is done on the Self Assessment return. The circumstances where this matters for a sole-trader locum are uncommon.
- Transitional rules. If you move from accruals to cash basis (or vice versa), transitional adjustments apply. For a locum who has always operated on a cash basis, this is not a concern; for one who is changing approach, the transition calculation should be done correctly.
The key practical point is this: record income when you receive it and costs when you pay them. Keep bank statements, agency remittance advices and receipts. Year-end is much simpler when the records match actual money flows.
MTD for Income Tax from April 2026
Making Tax Digital for Income Tax (MTD ITSA) changes how sole traders report income to HMRC. Instead of one annual Self Assessment return, in-scope taxpayers submit quarterly updates of income and expenses to HMRC via MTD-compatible software, followed by an end-of-period statement and a final declaration.
The thresholds are:
- From 6 April 2026: mandatory for sole traders and landlords with qualifying income above £50,000 a year (qualifying income broadly means self-employment income plus UK property income).
- From 6 April 2027: mandatory for those with qualifying income above £30,000 a year.
For a locum pharmacist earning above the relevant threshold, the practical steps are:
- Check whether you are in scope. If your gross locum income (before expenses) exceeds £50,000 in the 2024/25 or 2025/26 tax year, you should be preparing for MTD from April 2026. Use HMRC's eligibility check as the starting point.
- Choose MTD-compatible software. HMRC maintains a list of approved software providers. The software must be capable of submitting quarterly updates directly to HMRC's API. Not all accounting apps in common use are MTD-ITSA-ready; check the current approved list at gov.uk.
- Move to quarterly record-keeping. Records must be maintained and updates submitted quarterly (April to June, July to September, October to December, January to March), with the quarterly submission due one month after the quarter end. This is a shift from the once-a-year reconciliation that many sole traders currently rely on.
- Submit the end-of-period statement. After the four quarterly updates, an end-of-period statement finalises the year's figures and allows any adjustments (for example, claiming overlap relief, loss relief or allowances not captured in the quarterly updates).
- File the final declaration. The final declaration replaces the old tax return, confirming the income figure and triggering the tax calculation and payment liability.
Locums below the threshold in any given year are not in scope that year, but the threshold drops further (and may drop again in future). Sole-trader locums earning between £30,000 and £50,000 should be watching the April 2027 deadline and making sure their record-keeping is in shape to meet it.
MTD does not change what is allowable as an expense. It changes when and how the records are submitted. The pharmacist-specific expense set above applies unchanged under MTD; the difference is that those expenses are entered into the quarterly update as they occur, rather than being assembled once a year at filing time.
Working out what you keep, and getting it right
The expenses in this article reduce your taxable profit, but the final take-home depends on your total income, the tax bands that apply, whether you have other income, and your operating structure. The locum take-home comparator lets you model scenarios: sole trader vs limited company vs umbrella, at different income levels, to see where the tax and NIC numbers land. It is a scenario and estimate tool that states its simplifications and is not a filing-ready calculation for your specific position.
The comparator is a useful starting point. Getting the expenses right, confirming the status position, and ensuring the recording basis and MTD obligations are met are the next steps. For most sole-trader locums, these are not individually complex, but they interact: a status question changes whether the expenses arise at all; a cash-basis election changes when items are recognised; an MTD obligation changes the cadence of the whole process.
The locum pharmacists hub covers the full range of tax and accounting considerations relevant to locum pharmacists, including status, structure and compliance. This post covers expenses and Self Assessment mechanics; the hub links the other pieces together.
This article covers the position in England. The NHS locum booking landscape in Scotland, Wales and Northern Ireland involves different regulatory frameworks; the tax and status rules described here are UK-wide but the NHS contract context differs. All figures are for the 2026/27 tax year unless stated. This content is general guidance, not personal advice on your specific circumstances.