[CTM92005] Corporation Tax self-assessment (CTSA): the payment obligation: general
Companies must calculate their tax liability and pay this to HMRC by the normal due date. This obligation arises automatically and does not depend on any action by HMRC. Payment must be made electronically.
If the company is ‘large’, within the meaning of The Corporation Tax (Instalment Payments) Regulations 1998, it must pay its liability in instalments for CTSA accounting periods, see CTM92500 onwards.
The company will need to make further payments if it finds that its estimate has been too low. Also, it can claim a repayment if it later believes that the initial payment was too high, see CTM92090 and CTM92110.