Key points
- If it is your first time, you typically need to register for Self Assessment by 5 October following the end of the tax year.
- Online returns and payment are commonly due by 31 January; if you have payments on account, the second payment is often due 31 July.
- Treat SA like a micro-process: 10 minutes/week beats a 10-hour January scramble.
- Your ‘evidence’ stack: P60/P45/P11D (if relevant), invoices, mileage log, bank statements, and receipts for allowable costs.
- Never file based on vibes. Reconcile income + expenses first, then submit.
The deadlines clinicians actually miss (and how to stop doing that)
These dates are non-negotiable calendar anchors for most people filing SA:
• Register (first time): typically by 5 October after the end of the tax year.
• Paper return: typically by 31 October.
• Online return + tax payment: typically by 31 January.
• Second payment on account (if applicable): typically by 31 July.
Your solution is not motivation. It is a system: a monthly ‘reconciliation day’ and a tax reserve account.
Who needs Self Assessment in the real world (doctor edition)
Common triggers for clinicians include: locum income paid gross (self-employed/sole trader), income streams outside PAYE, certain types of untaxed income, and situations where HMRC requires a return.
If you are PAYE-only, you may not need SA, but do not assume. The correct move is: check your HMRC account, check any HMRC letters, and speak to an accountant if your income profile is multi-stream.
First-time setup (30 minutes, once)
1
1) Create/access your HMRC online account
Make sure you can sign in reliably. Store recovery codes safely. If you cannot log in smoothly, everything downstream breaks.
2
2) Register for Self Assessment (if required)
If this is your first time and you need SA, register early. The friction is not the form; it is waiting for post/credentials while January approaches.
3
3) Build a single ‘SA folder’ (physical or digital)
Create subfolders: Income, Expenses, Mileage/Travel, Pension/Benefits, HMRC Letters, Prior Returns. This reduces decision fatigue.
4
4) Create a weekly capture habit (10 minutes)
Every week: file receipts, update mileage, and note any unusual payments. You are preventing ‘memory-based accounting’.
5
5) Set a monthly reconciliation day
Once a month: total locum income, match to bank entries, and sanity-check expenses. This becomes your ‘pre-filing’ work.
6
6) Ring-fence tax (do not trust yourself)
Move a fixed % of gross locum income into a separate ‘Tax Reserve’ account immediately on payment. Adjust later, but always reserve early.
The most common clinician error
Treating Self Assessment as a January admin task.
It is not. It is a year-round recordkeeping workflow. The filing is the final click — the work is done in the 12 months before.
PAYE + locum income: how to avoid the classic confusion
If you have multiple income streams (e.g., a salaried post plus locum sessions), your filing workload is not ‘double’ — but your error risk is.
Practical rule: keep a separate bank account for locum income/expenses where possible, so your bookkeeping is not mixed with life spending.
5-minute pre-submit checklist
Before you submit:
1) Income totals match bank totals (no missing invoices).
2) Expenses are defensible in one sentence each.
3) Mileage/travel has dates + purpose.
4) You understand whether payments on account apply.
5) You have saved a PDF copy of the submission and your working notes.
SourceGOV.UK — Self Assessment: deadlines (official)
Open Link SourceGOV.UK — Register for Self Assessment (official)
Open Link SourceGOV.UK — Payments on account explained (official)
Open Link References
Save your place and choose what comes next
Work through this guide (6 steps)
Use the actions from this article to track what you have worked through.
Sign in using the reading controls above to save your steps.
Make sure you can sign in reliably. Store recovery codes safely. If you cannot log in smoothly, everything downstream breaks.
Return to this sectionIf this is your first time and you need SA, register early. The friction is not the form; it is waiting for post/credentials while January approaches.
Return to this sectionCreate subfolders: Income, Expenses, Mileage/Travel, Pension/Benefits, HMRC Letters, Prior Returns. This reduces decision fatigue.
Return to this sectionEvery week: file receipts, update mileage, and note any unusual payments. You are preventing ‘memory-based accounting’.
Return to this sectionOnce a month: total locum income, match to bank entries, and sanity-check expenses. This becomes your ‘pre-filing’ work.
Return to this sectionMove a fixed % of gross locum income into a separate ‘Tax Reserve’ account immediately on payment. Adjust later, but always reserve early.
Return to this section
Finances · Article 6 of 16