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HMRC internal manual

COTAX Manual

CT Pay and File: returns / notices: return handling: mismatched returns

When, exceptionally, you receive a paper return that does not match a live AP on COTAX, Function LRTN (Log Return) allows you to amend the AP structure. If you are unable to do so, the case is listed on AAPR (Amend Accounting Period List) and is referred to as a ‘mismatch’. COM132034 has further guidance on this subject and the circumstances under which you may correct a return.

Under the appropriate legislation, it is for the company in the first instance to determine the period for which a return should be made. However, the position alters when it comes to the assessment. Under CT Pay and File, the caseworker makes the assessment and therefore determines the period for which it should be made.

Where clerical staff cannot log a CT Pay and File return on receipt, a caseworker must deal with the return following the COM157112 Action Guide.


  • COM157011 for a list of forms relevant to this subject
  • COM157021 for a list of functions to use in particular situations
  • COM157022 for legislation applying to this subject.