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HMRC internal manual

COTAX Manual

CT Pay and File: assessments: manual assessments

Exceptionally, you may need to manually make or amend a CT assessment for a CT Pay and File AP. This may be when

  • COTAX is unavailable and you have to make an assessment urgently


  • You have made an invalid assessment. For more information see COM151120 

You prepare manual assessments using

  • Form SEES 310(Z) to make or amend an assessment

When you use Function PAST (Prepare Full Assessment) to record the issue of a manual assessment, COTAX does not issue any output.


  • Retains the details of the manual assessment on the record for the company
  • Does not accept a manually issued assessment containing an arithmetical error. If you have made such an error, you must issue a manual amendment and record those details on COTAX
  • Records the relevant postings, as if it had made the assessment (or amendment)

You can subsequently use Function PAST to amend the manual assessment, or make a further assessment in the normal way.

For a list of forms relevant to this subject, see COM151021.

For a list of functions to use in particular situations, see COM151011.