Returns / notices: notices and returns: HMRC Corporation Tax online filing software
HMRC provides an online version of the form CT600 which is available through the Corporation Tax Online Service.
The application enables companies to submit supplementary pages CT600A, CT600E and CT600J.
A company is excluded from using the HMRC product if it needs any of the other supplementary pages or needs to make various excluded entries in the accounts or computation. Those excluded from using the HMRC product must use a commercial software package instead. COM60040 shows you a list of the exclusions.