When you stop being a salaried doctor and start invoicing as a locum, your tax bill suddenly becomes something you can influence. Every legitimate business expense you claim reduces the profit you pay tax on. Miss them, and you're handing money to HMRC that you didn't owe.
But the rules aren't always intuitive — especially around travel, training, and anything you use for both work and personal life. Here's a practical guide to what self-employed locum doctors can claim, what they can't, and the bits that catch people out.
The "wholly and exclusively" rule
HMRC's core test for any self-employment expense is that it must be incurred wholly and exclusively for the purposes of your trade. That phrase does a lot of work. It means you can't claim something that has any meaningful personal benefit unless you can split out the business portion.
A new laptop you only use for clinical admin? Fully claimable. A laptop you also use for personal email and Netflix? Claim the business proportion only.
Keep this rule in mind for everything below.
What you can claim
The categories that apply to most locum doctors:
Professional indemnity — MDU, MPS, or MDDUS premiums are fully claimable. This is usually one of the larger annual costs you'll have.
Professional subscriptions and registrations — GMC registration, BMA membership, Royal College fees. All allowable as long as they're required or relevant to your work.
CPD and training — Courses, conferences, and refresher training that relate to the work you currently do. The catch: training that qualifies you for a new line of work isn't allowable. Updating skills for your existing practice is fine; cross-training into a different specialty often isn't.
Travel between work locations — Travel between practices on the same day, or to a temporary work site, is generally claimable. Travel from home to a regular workplace isn't — but as a locum, what counts as "regular" depends on your working pattern. More on this below.
Mileage — If you use your own car for business travel, you can claim HMRC's approved rates: 45p per mile for the first 10,000 business miles in a tax year, then 25p per mile after that. Keep a log of dates, destinations, and miles.
Equipment — Stethoscopes, otoscopes, BP cuffs, clinical bags, a laptop or tablet used for work. Items used partly for personal life need apportioning.
Phone and broadband — Claim the business proportion. If you use your mobile 30% for work calls and admin, claim 30% of the bill.
Home office costs — If you do work admin from home (and most locums do), you can claim a proportion of your household running costs. HMRC offers a flat-rate "simplified expenses" option based on hours worked from home, or you can calculate the actual proportion based on rooms and time.
Accountancy and software fees — Including subscriptions to MTD-compatible software like Duly Filed.
Stationery, printing, postage, work-related books and journals — All allowable if used for work.
The bits that catch people out
A few things consistently trip up locum doctors:
Home-to-work travel is the big one — and it's more nuanced than most people realise. HMRC's rule is that travel from home to a regular workplace is commuting, not business travel, even if you're self-employed. Commuting isn't claimable. But what counts as a "regular workplace" depends entirely on your working pattern.
If you genuinely work at different practices on different days — three surgeries on three different days, or a rolling list of bookings that changes week to week — there's no single regular workplace. Every site is a temporary one. Travel from home to each of them is allowable business travel.
If you work at the same practice most weeks — say a Monday slot at one surgery you've held for the last year — HMRC is likely to treat that as your regular workplace. The journey is commuting and not claimable, even though you're self-employed and only there one day a week.
The grey area is in between. There's no hard rule on how often is "too often", but the more consistent and long-running the pattern, the more it looks like commuting. A useful test: if a tax inspector looked at your diary for the year, would they see one place you went most often, or genuine variety? The more variety, the safer the mileage claim.
If you have a mix — some regular slots and some genuinely temporary ones — claim the travel to the temporary sites and leave the regular ones alone.
Clothing isn't allowable. Even smart workwear or scrubs you only wear at work. The HMRC rule is strict here: clothing has a "duality of purpose" because it also keeps you warm and decent. Specialist protective equipment is the narrow exception.
Meals during a normal working day aren't claimable. You'd have to eat anyway. Meals during overnight stays for work, or genuine business entertainment, can be allowable.
Reimbursed costs aren't expenses. If a practice or agency reimbursed you for something, you can't also claim it as an expense — that's double-counting.
NHS pension contributions don't go in your trading expenses. Your employee NHS pension contributions belong in the personal pension contributions section of your tax return, not your self-employment expenses. They still attract tax relief, just in a different place.
How to actually track everything
The cleanest approach is to log expenses as you go, monthly at the latest. Two reasons: receipts get lost, and you'll forget what something was for if you leave it more than a few weeks. Under MTD, this isn't optional — digital record-keeping is a requirement.
A few practical habits that make life easier:
- Use a separate bank account or card for business spending. It doesn't have to be a fancy business account — just a dedicated personal account works for sole traders, and it makes everything easier to track.
- Photograph receipts the day you get them. Paper fades.
- Categorise as you go, not at the end of the year. Trying to remember in January what a £42 Amazon order in June was for is a losing game.
- Keep a mileage log. A note on your phone is fine — date, destination, purpose, miles.
Duly Filed is built around exactly these categories — MDO indemnity, GMC, CPD, clinical equipment, mileage, and the rest are pre-configured so you can just start logging. You can rename, add, or remove rows to fit how you actually work, and everything saves automatically.
Sign up for Duly Filed to track your locum expenses without the spreadsheet.
This post is for general information only, not tax advice. Rules and rates are accurate as of April 2026 but change. If you have a complex setup — limited company, mixed PAYE and self-employment, or significant capital purchases — speak to a specialist medical accountant.