You are the first person to arrive at the scene of an accident with injured persons. What should you do first as a rule?

As a rule, the first priority is to secure the accident scene (“make the scene safe”) so that no further crashes happen and so you and the injured are not put in additional danger. If you become a casualty yourself or another vehicle crashes into the scene, helping the injured becomes harder or impossible.

In practice this means: stop in a safe position, switch on hazard warning lights, put on a high-visibility vest if available, place a warning triangle at a suitable distance (farther away on faster roads), and warn/slow approaching traffic. Only when the scene is reasonably secured should you move on to the next steps: call emergency services and give first aid.

Calling from the next telephone box is not “first” because leaving the scene can waste time and the unprotected accident site remains dangerous. Checking injury severity is important, but you can only do it safely once traffic and other hazards are under control. A useful rule of thumb is: self-protection and scene safety first, then emergency call, then first aid.