Self Assessment filing deadline

By Tolley

The following Personal Tax guidance note by Tolley provides comprehensive and up to date tax information covering:

  • Self Assessment filing deadline
  • Usual deadlines
  • Exceptions to the rule
  • Filing deadline for underpayments to be collected via PAYE
  • Client authorisation for Tax Return submission
  • Penalties for late filing

Usual deadlines

There are two dates by which a Self Assessment Tax Return should be filed:

  • 31 October following the end of the tax year (paper submission)
  • 31 January following the end of the tax year (three-month extension for online filing)

TMA 1970, s 8(1D)

Therefore, for the tax year 2017/18, the paper Return must normally be filed by 31 October 2018. For an electronic return, the filing deadline is 31 January 2019.

For a template letter that could be used to remind clients to submit their information, see the Standard document ― 2017/18 Tax Return reminder letter.

Exceptions to the rule

There are exceptions to the 31 October / 31 January deadlines depending on the date the Tax Return was issued.

For those taxpayers who file Tax Returns every year, a Return will normally be issued on 6 April following the end of the tax year. Where a taxpayer is required to notify his chargeability to HMRC, the date of issue will be later. See the Notification of chargeability to income tax and capital gains tax guidance note.

Returns issued between 6 April and 31 July

For Tax Returns issued between 6 April and 31 July after the end of the tax year, the usual deadlines apply:

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