If all the emergency services are on their way, it's possible that a major incident or disaster has happened. Suddenly many rescuers will be working at the same scene of devastation.
Emergency plans establish who does what and where beforehand.
The best way of testing these arrangements is through an emergency exercise . The police , ambulance and fire services know their territories well and so do local authorities . But the Home Office has many other emergency planning functions. For example, it helps government ministers react to major incidents, alerts them when there's a threat to public safety from, for example, a rogue satellite, comet, severe storms or unexploded bombs. Each bit of government in England, Wales , Northern Ireland and Scotland has an assigned role to play in a major disaster and is known as the lead government department according to its area of expertise and responsibility.