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HMRC internal manual

Compliance Handbook

Interest: late payment interest: special provisions: special provisions for start dates: amended assessments and discovery assessments

You must check whether, and from which date, the FA 2009 interest rules apply to the tax or duty you are dealing with. See CH140160 for full details.

A special provision changes the general rule, see CH141120, and applies where

  • an assessment or self-assessment is corrected or amended, or
  • HMRC issues an assessment in place of, or in addition to, a person’s self-assessment, or
  • HMRC issues an assessment in place of a self-assessment that a person should have made.

In all these cases, the late payment interest start date for the tax charged by the amendment or assessment is the date on which tax would have been due and payable if the original assessment had been complete and accurate, and made at the correct time.

The extra tax charged that is due and payable because of the correction or amendment is the amount on which late payment interest is calculated.

Where a person’s notice to file a self assessment tax return is withdrawn, see CH61700, but they have to notify chargeability to income tax or capital gains tax under section 7(1B) TMA 70, late payment interest starts from the due date for payment that would have applied had the original notice to file not been withdrawn.