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From 6 January 2024, the main rate of class 1 National Insurance contributions (NIC) deducted from employees’ wages is reduced from 12% to 10%. From 6 April 2024, the main rate of self-employed class 4 NIC will reduce from 9% to 8% and class 2 NIC will no longer be due. Those with profits below £6,725 a year can continue to pay class 2 NIC to keep their entitlement to certain state benefits. Our guidance will be updated in full in spring 2024.

Updated on 6 April 2023

Tax: HMRC determinations of tax liability

If you were supposed to submit tax returns to HMRC but have not done so, they may have sent you a ‘determination’ of the tax they think you owe. 

Content on this page:

What a determination is

Where HMRC have asked you to complete tax returns but you have not done so, HMRC might take steps to recover from you the tax they think you owe.

They will use what they do know about you – perhaps from previous tax returns, or from other data they have received from third parties – to calculate an estimate of how much tax they think you should pay for the relevant tax year(s).

HMRC will then issue this to you as a formal ‘determination’ of your liability and you will then either have to pay this or take action, as we explain below.


HMRC cannot send you a determination after the third anniversary of the date the return was originally due to be filed.

For example, for a 2019/20 tax return HMRC’s ‘final date’ for issuing a determination would usually be three years from 31 January 2021, which is 31 January 2024.

If HMRC issue a determination

Note that even though a determination is an estimated amount, it is a legally enforceable debt, unless you submit the outstanding return within:

  • 12 months of receiving the determination, or
  • three years from the filing date of the outstanding return to which the determination relates (if later).

You should therefore submit the outstanding return as soon as possible after receiving the determination. The amount owed on that return will then replace the amount of the determination.

If you miss the deadline for submitting the return

If you miss the deadline for submitting your return after receiving the determination, then the determination stands unless HMRC agree a claim you might make for ‘special relief’. For more on this claim, see the detailed information provided by the tax charity, TaxAid.

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