Accountants for Locum Dentists: 2026 Guide
Most associate and locum dentists assume that signing a standard associate agreement automatically settles their tax status. It doesn’t u2014 HMRC looks at how you actually work, not just what the contract says, and getting this wrong can mean a backdated tax bill going back years. This guide from Filing Accounts UK covers what locum and associate dentists genuinely need to know, using only verified facts from HMRC guidance.
At Filing Accounts, we work with associate and locum dentists across the UK, helping structure their finances correctly from the outset.
Your Associate Agreement Isn’t the Whole Story
Most self-employed associate dentists work under a version of the BDA model associate agreement, a widely used template. Here’s the part that catches people out: using this agreement doesn’t automatically guarantee self-employed status. HMRC and tax tribunals look at your actual working conditions, not just the paperwork, and test things like:
- Substitution u2014 can you genuinely send a qualified locum in your place if you’re unavailable?
- Financial risk u2014 do you personally bear costs like lab fees and your own indemnity cover?
If your day-to-day working arrangement doesn’t genuinely reflect these tests, you’re at risk of being reclassified as an employee for tax purposes u2014 and HMRC can issue backdated tax and National Insurance going back 4 years where reasonable care was taken, 6 years for carelessness, and up to 20 years if the position is considered deliberate. Having your associate agreement and actual working practices reviewed by someone who understands this area, before HMRC ever asks, is genuinely worthwhile protection.
Do You Need to File a Tax Return?
Almost always, yes. Most associate dentists are self-employed for tax purposes, and once your self-employment income exceeds the £1,000 trading allowance, you must register for Self Assessment and file. This applies even to a dentist who’s mainly salaried elsewhere but picks up locum, private, or teaching income on the side u2014 that additional income still needs declaring in its own right.
What You Can Actually Claim
Generally Allowable
- Professional indemnity insurance u2014 Dental Protection, the MDU, or MDDUS
- GDC annual retention fee u2014 the cost of keeping your name on the register so you can practise
- Approved professional subscriptions u2014 bodies on HMRC’s List 3, including the BDA, FGDP, and relevant specialty societies
- CPD genuinely relevant to your existing practice u2014 training that instead creates a wholly new skill is generally treated as capital, not a straightforward expense
- Loupes and instruments u2014 usually relieved through capital allowances and the Annual Investment Allowance rather than as a simple revenue expense
- Mileage between different practices u2014 at approved rates of 45p per mile for the first 10,000 business miles, 25p after
- Home office, on a fair apportionment for admin work u2014 many associates use the simplified flat rate (£10 to £26 a month depending on hours) rather than calculating actual costs
- Accountancy fees and business bank charges
Not Allowable
- Home-to-regular-practice commuting u2014 travel to a single, regular practice is ordinary commuting, not business mileage. Travel between different practices is a different matter and generally does qualify
- The GDC restoration fee u2014 unlike the annual retention fee, this isn’t deductible, since it stems from a personal lapse in registration rather than an ongoing cost of trading
- Any CPD shortfall penalty
Sole Trader, Partnership, or Limited Company?
Most associates operate as sole traders, and it remains the simplest and most common structure for locum and associate work. Practice owners are more likely to consider a limited company, generally for the Corporation Tax and dividend efficiency once profits reach a meaningful level u2014 though incorporating brings IR35 into the picture if you’re supplying services through a personal service company, so this needs weighing up properly rather than assumed automatically.
National Insurance for Self-Employed Dentists
Self-employed associates pay Class 4 National Insurance at 6% on profits between the lower and upper profits limits, and 2% above that u2014 in addition to Income Tax on the same profits. This is a different NIC structure entirely from an employed dentist’s Class 1 contributions, and it’s worth understanding both when weighing PAYE employment against self-employed associate work.
Making Tax Digital: Now Live for Many Associates
Since 6 April 2026, self-employed associates with qualifying income above £50,000 must follow Making Tax Digital for Income Tax, keeping digital records and submitting quarterly updates rather than filing a single annual return. This threshold falls to £30,000 from April 2027 and £20,000 from April 2028, bringing more associates into scope over time.
Locum Dentist Tax at a Glance
| Item | Detail |
|---|---|
| Common structure | Self-employed associate under the BDA model agreement |
| Registration threshold | £1,000 trading allowance |
| Class 4 NIC | 6% between profits limits, 2% above |
| GDC annual retention fee | Allowable |
| GDC restoration fee | Not allowable |
| Backdated reclassification risk | 4, 6, or 20 years depending on behaviour |
| MTD threshold (2026/27) | Over £50,000 qualifying income |
Common Mistakes to Avoid
Assuming the Associate Agreement Alone Settles Your Status
HMRC looks at how you actually work day to day, not just the contract’s wording u2014 mismatches between the two are a real reclassification risk.
Claiming the GDC Restoration Fee
This is treated differently from the annual retention fee u2014 it stems from a personal registration lapse and isn’t deductible.
Claiming Loupes and Instruments as a Simple Expense
These typically go through capital allowances instead, which changes how and when the tax relief is given.
Overlooking Small Side Income
Locum, private, or teaching income alongside a main salaried role still needs declaring once it crosses the £1,000 threshold, even if it feels incidental.
Frequently Asked Questions
Does using the BDA model agreement guarantee self-employed status?
No. HMRC assesses your actual working conditions against tests like substitution and financial risk, not just the agreement wording.
Can I claim my GDC fees?
The annual retention fee is allowable. The restoration fee, if your registration lapsed, is not.
Do I need to file a tax return if I only do occasional locum work?
Yes, once your self-employment income exceeds £1,000 in a tax year, even if it’s alongside a main salaried role.
How are loupes and dental instruments treated for tax?
Usually through capital allowances and the Annual Investment Allowance, rather than as a straightforward expense deduction.
Need an Accountant Who Understands Dental Associates? Talk to Filing Accounts UK
Getting your status, expenses, and structure right matters more than most associates realise, especially with reclassification risk reaching back years. At Filing Accounts, we help locum and associate dentists structure their finances correctly and claim what they’re genuinely entitled to.
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