Stay calm, shout for help. You may need to instruct someone to telephone 999. Make sure they know where the ambulance has to come to, and they have some details about the person who is injured or ill.
Don't put yourself in danger. For example, if someone has been electrocuted, make sure you switch off the power supply before touching them. Do everything you can to help the person.
Don't give the person anything to eat, drink or smoke. Don't stick anything in their mouth.
Follow the instructions the ambulance service call handler may give you.
The way to help a person very often depends on what is wrong with them. Sometimes, the quickest way to help is to take the person to the nearest accident and emergency department. This will vary from area to area as it does depend on how close your local hospital is. However, even in an area where your hospital is fairly close, you should call an ambulance and not move the patient if:
you think they may have hurt their back or neck, or have any other injury that may be made worse by moving them,
the person is in shock and needs your constant attention, or
the person has severe chest pain or difficulty breathing.
Reference [NHS Choices]