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HMRC internal manual

Enquiry Manual

HM Revenue & Customs
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Interest: SA 1996-1997 and Later Years





Relevant dates

Interest runs from the relevant date until payment and is directly related to the year of assessment.

Payments on Account (S59A(2) TMA70)

The relevant dates are

  • 31 January within the year of assessment (based on 50 per cent of the previous year’s net income tax liability)
  • 31 July immediately following the end of the year of assessment (again based on 50 per cent of the previous year’s net income tax liability)

subject to any claim to reduce the payment due see EM4660.

Balancing Payments (S55 TMA70 or S59B TMA70)

The relevant date is

  • 31 January immediately following the end of the year of assessment.

Note: The only exception is where the taxpayer has notified chargeability by 5 October following the year of assessment but HMRC has failed to send a notice to make a return to that person by 31 October (S8 TMA70). The relevant date in this situation is three months from the date on which the notice to make a return was given.

Due Dates and Relevant Dates

The due date for payment is not always the same as the relevant date for Section 86 interest.


A discovery assessment is made under S29 TMA70 on 31 October 2007 in respect of additional liability for the year 1997-98. Although the tax on that assessment is payable 30 days after the date of issue of the assessment, 30 November 2007 (S59B(6) TMA70), interest will run from the S86 relevant date of 31 January 1999.


Under SA, partnerships do not pay tax, the individual partners do.

But 1996/97 was a transitional year and an ‘old’ partnership (see EM7001) was subject to assessment in the partnership name. For these assessments the pre-SA version of S86 and S88 apply regardless of the date on which the assessment is made. If help is needed approach contact link.

Contract Settlements

See EM6005+ for guidance on how to calculate S86 interest in a contract settlement.