The Safety Representatives and Safety Committees Regulations 1977 provide for the appointment of safety representatives where there is a recognised trade union. Also, where safety representatives request it, the Regulations provide for the setting up of a safety committee. Where there is no recognised union, the Health and Safety (Consultation with Employees) Regulations 1996 will apply.
If there is a union, you should meet to choose a safety rep and then inform your employer about your choice.
If there is no union, you should approach your employer and ask them to arrange for the appointment or election of representatives to take place. However, union-backed safety reps will be more effective, as they will be able to draw on the advice and help of their union.