Certain accidents, diseases, and other incidents, such as near misses, which happen at work, have to be reported. This includes both employees and members of the public. The legal requirement to do this is known as RIDDOR.
This is to allow us, or the Health and Safety Executive, to investigate the matter fully.
A record should be kept of all accidents at work, even ones which don't need to be reported. This can be done in an accident book.