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HMRC internal manual

COTAX Manual

Penalties: late delivery of returns: period of determination

Late filing penalties can be flat-rate in set amounts or tax-related in amounts that are based on the tax liability for the return period and the amount of that liability that remains unpaid 18 months after the end of the AP.

Exceptionally, if the filing date for the return is more than 18 months after the end of the AP, then the penalty is based upon the tax unpaid at that later date.

These penalties are chargeable in relation to an AP, but a notice to deliver can cover more than one AP, so that two or more penalties can be chargeable in respect of one notice.


  • records occurrences of penalty liability for each specified period by reference to the return or returns believed to be due in response to the notice to deliver
  • brings together into a single penalty determination all the flat-rate or all the tax-related penalties incurred for failure to make the returns required by a single notice to deliver
  • automatically issues determinations, where appropriate.

COTAX does not mix flat-rate and tax-related penalties in the same determination. This means that when there is more than one return period in a specified period, one determination is made for each class of penalty incurred.

Once you have charged a penalty by a determination you can only amend it under S100(6) TMA 1970 or on appeal.

If there has not been an appeal, you may wish to make a further determination if you discover that a determination is insufficient.

Where COTAX has not already done so, you make main or further determinations for both flat-rate and tax-related penalties using function PPEN (Prepare Penalty Determination).


  • COM100011 for a list of forms relevant to this subject
  • COM100012 for a list of functions to use in particular situations
  • COM100013 for legislation applying to this subject.