If someone is injured in an incident, first check that you and the casualty aren't in any danger. If you are, make the situation safe.
When it's safe to do so, assess the casualty and, if necessary, dial 999 or 112 for an ambulance. You can then carry out basic first aid.
The 3 priorities when dealing with a casualty are commonly referred to as ABC, which stands for:
If the casualty appears unresponsive, ask them loudly if they're OK and if they can open their eyes.
If they respond, you can leave them in the position they're in until help arrives.
While you wait, keep checking their breathing, pulse and level of response:
If there's no response, leave the casualty in the position they're in and open their airway.
If this isn't possible in the position they're in, gently lay them on their back and open their airway.
To open the airway, place 1 hand on the casualty's forehead and gently tilt their head back, lifting the tip of the chin using 2 fingers. This moves the tongue away from the back of the throat.
Don't push on the floor of the mouth, as this will push the tongue upwards and obstruct the airway.
If you think the person may have a spinal injury, place your hands on either side of their head and use your fingertips to gently lift the angle of the jaw forward and upwards, without moving the head, to open the airway.
Take care not to move the casualty's neck. But opening the airway takes priority over a neck injury. This is known as the jaw thrust technique.
To check if a person is still breathing:
If they're breathing normally, place them in the recovery position so their airway remains clear of obstructions, and continue to monitor normal breathing.
Gasping or irregular breathing is not normal breathing.
If the casualty isn't breathing, call 999 or 112 for an ambulance and then begin CPR.
If the casualty isn't breathing normally, you must start chest compressions immediately.
Agonal breathing is common in the first few minutes after a sudden cardiac arrest (when the heart stops beating).
Agonal breathing is sudden, irregular gasps of breath. This shouldn't be mistaken for normal breathing and CPR should be given straight away.
These pages provide information and guidance about common first aid situations. But they aren't a replacement for taking a first aid training course.
Basic first aid courses are run regularly in most areas around the UK. St John Ambulance, British Red Cross, NHS Ambulance Service and St Andrew's First Aid all provide a selection of first aid courses.