999 – The main emergency number. This number should be used only when urgent attendance by the emergency services is required.
111 – NHS Direct service. Use this for illnesses and minor injuries where life isn’t threatened, but you would like some advice on what to do next.
101 – Call this number if you want to contact the police, but it’s not an emergency.
112 – This operates exactly the same as 999 and directs you to exactly the same emergency call centre. However 112 will work on a mobile phone anywhere in the world.