Employer and trade union
If the deceased was working, you should inform their place of work as soon as possible. You can do this either by asking for the Human Resources (Personnel) department if the organisation is large enough to have one, or their line manager. They will take responsibility for informing colleagues. They will be also able to arrange for any outstanding pay to be released to the estate, and tell you about any death in service benefit.
School, college or other educational establishment
If a pupil/student has experienced a significant bereavement you may want to let the school/college know so they can be aware if additional support is needed. It is important to discuss this with the child/young person concerned so they are aware and have given consent if they are of an age to do so.