Self Assessment for GP locums: registration, records, deadlines and payments

Self-employment is one common reason to file, but HMRC's criteria cover other circumstances. A salaried GP can still need Self Assessment for locum profit. Check HMRC's current criteria and any notice to file. Keep contracts and seek advice where ‘locum’ work could instead be employment, agency or company work.

If you need to report new self-employment, use the official HMRC registration route. A first-time filer is normally expected to tell HMRC by 5 October following the end of the relevant tax year, although the practical requirement depends on why a return is due and any existing record. Register early enough to receive access details before January.

The Unique Taxpayer Reference identifies the Self Assessment record. It is not the same as a National Insurance number, GMC number or Government Gateway user ID. Store the UTR securely, keep recovery details current and do not send sign-in credentials to an accountant. Accountants use an authorised-agent process rather than your password.

The tax year runs from 6 April to 5 April. Reconcile sessions, payments, expenses, mileage and pension records monthly, then close the full year after 5 April. Standard dates include 31 October for paper returns and 31 January for online returns and balancing payments. Payments on account can also fall on 31 January and 31 July.

Keep both the work/invoice date and the bank paid date. The applicable accounting basis determines when amounts are recognised, and year-end adjustments may be needed. Cash basis broadly follows money received and paid; traditional accounting broadly follows income earned and expenses incurred. Rules and eligibility can change, so confirm the basis used in the return.

An unpaid invoice crossing 5 April is a good test of record quality. Do not delete it from the old year or treat it as paid because the work happened. Keep the session, invoice, due status and eventual receipt connected, then let the accounting basis decide the return treatment.

Many GPs combine PAYE work with self-employed locum sessions. The return brings relevant sources together; PAYE tax already deducted may not cover locum profit. Keep P45, P60 and P11D documents and flag professional costs shared between roles rather than claiming them twice.

Expense records need supplier, date, amount, business purpose, receipt and any private or reimbursed element. Mileage needs journey date, origin, destination, purpose and distance. A total reconstructed from a calendar is weaker than a contemporaneous journey log.

NHS pension documents are not interchangeable with expense entries. Preserve the session, pensionable-pay context, Locum A/B or other official records, contributions paid and dates. An accountant can assess the tax-return entries; airGP does not decide pension eligibility or authoritative contribution figures.

Payments on account are advance instalments towards the next Self Assessment bill. HMRC normally calculates each as half of the previous year's relevant bill, with instalments on 31 January and 31 July. They are generally not required where the relevant bill is below the current threshold or most tax was collected outside Self Assessment; check the live rules.

This is why a first substantial January payment can feel larger than one year's balancing amount. A claim to reduce payments on account may be possible if the next bill is genuinely expected to be lower, but reducing too far can lead to interest. Use current figures and accountant advice rather than changing them to solve short-term cash flow.

No single percentage is safe for every GP. PAYE income, tax bands, profit, National Insurance, student loans, pension, other income and payments on account all matter. Ring-fence money as payments arrive and ask an accountant for an in-year forecast based on actual figures.

Ask the accountant what format and cut-off date they prefer. Reconcile totals to the bank and list missing receipts, disputed invoices, equipment, mixed costs, uncertain travel and reimbursements. Use HMRC's agent-authorisation process rather than sharing your Government Gateway password.

Do not ignore an error because a return was submitted. HMRC provides amendment and disclosure routes with time limits. The right action depends on the error and timing. Tell the accountant promptly, preserve the corrected source record and avoid editing historical exports without an audit note.

Late filing and late payment can create separate penalties and interest. If records are incomplete, submit accurate information using the appropriate process rather than inventing precision. Contact HMRC or seek professional help early when illness, access problems or missing data threaten a deadline.

MTD for Income Tax adds digital records and quarterly updates for eligible people in phases; it does not remove year-end information or tax payment. Keep reliable source records and check current thresholds. airGP's optional direct-submission add-on is coming soon and awaiting approval, not a live filing route.