Answer:
Well, each workplace varies.
In most cases you have a right to a witness if attending a scheduled meeting. They will inform you of this meeting in advance through a letter addressed to your home address. In most cases you are entitled to at least 2 verbal and a written warning before you get a final written warning. The management usually asks if there is anything which is affecting your personal life which, in turn, has brought upon the reason for said disciplinary. They will then proceed to offer assistance if they can (or are willing) provide it. The meeting will have documented notes which will be kept in your staff file for a minimum period of 6 months then destroyed.