IHTM10701 - Corrective account (C4): introduction
Form C4 is a corrective account. Taxpayers complete this form to tell us of amendments to the original account. They are required to deliver a corrective account (IHTM10805) within 6 months of discovering that the original account was incorrect.
While the requirement to advise us of defects in the original account remains in practice there are only a few circumstances (IHTM10702) where you should insist on the taxpayers completing a formal C4.
In Scotland the C4 doubles as a Corrective Inventory for the purposes of obtaining confirmation and where confirmation is to be obtained, a form C4(S) may accompany the main form.