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Tax returns

Self-assessment is a system HMRC uses to collect income tax. Tax is usually deducted automatically from wages, pensions and savings, but if you have other forms of income you may need to report them in a tax return.

Do I need to complete a tax return?

HMRC will not necessarily prompt you to complete a tax return, so you need to be aware of when you may need to complete one. For example:

  • do you have untaxed ad-hoc income of more than £2,500? This could include things like locum fees, crematorium fees and form-filling fee
  • are you claiming employment expenses, such as annual subscriptions to the BMA, MDU or GMC, of more than £2,500 a year?
  • are you domiciled outside of the UK?
  • do you have savings or investment income of more than £10,000?
  • do you receive rental income from a property of more than £2,500?
  • do you receive dividends from shares and pay tax at either the higher or additional rate of tax?
  • is your total income more than £100,000?
  • was your or your partner’s income over £50,000 as one of you claimed the child benefit?

If the answer to any of these questions is yes, you are legally required to submit a tax return and must register for self-assessment.
Please note this list is not exhaustive.

View the full list of the self-assessment criteria


What are the deadlines for completing a tax return?

You file a tax return after the end of the tax year (5 April) that it applies to.

The deadline for submitting a paper tax return is 31 October, whereas the deadline for submitting online is 31 January following the end of the tax year – if you haven’t done an online tax return before, allow extra time as you’ll need to register first.

If you do not submit your tax return by the deadline, HMRC can charge an instant penalty of £100, which increases the later the tax return is submitted.


How do I register?

You should tell HMRC by 5 October following the end of the tax year for which you need to complete a tax return. For example, if you require a tax return for the 2015/16 tax year that ends on 5 April 2016, the deadline to register is 5 October 2016. You may be financially penalised if you register late.

Register your filing requirement

You will then be issued with a 10-digit UTR (unique tax reference), which you use to complete your tax return online through the self-assessment section of the HMRC website.

If you prefer to submit a paper tax return to HMRC, download the form


What information do I need to help me complete a tax return?

  • forms P45 and P60 detailing your gross employment income received and tax withheld through PAYE
  • form P11D if you receive any taxable benefits or expenses as an employee, invoices or payment advice slips relating to any locum fees, cremation fees, form-filling fees
  • details of any tax-deductible expenses such as professional fees and subscriptions (see ‘Tax relief on employment expenses’ for more detailed information about this)
  • your payslips showing the amount of money paid towards student loans in the past tax year. If you have underpaid based on your earnings, HMRC will collect any extra money owed for your student loan.