The decision to declare a major incident (MI) is not one to be taken lightly, but a delay in doing so may have dire consequences. The aim of this study was to ascertain what factors make specialists from a variety of pro-fessional backgrounds in the United Kingdom determine from an initial visu-al assessment of a scene that a MI should be declared.

Participants were presented with three different scenarios, which were presented pictorially. Their responses were noted.

One hundred seventy-eight professionals took part in this study. For Scenario 1 (a road traffic incident), 101 (57%) declared a MI. For a coach rollover in Scenario 2, a MI was declared by 82 (46%) people, and a MI was declared by 156 (87%) for a rail crash in Scenario 3.

Forty-six participants had attended a MI previously.The results for declar-ing a MI in this group were: (1) Scenario 1, 25 (54%); (2) Scenario 2, 25 (54%); and (3) Scenario 3, 44 (96%). Of this group, 44 had previously had training before experiencing the MI. Those who had >10 years of service in emergency services were more likely to declare a MI in Scenario 2 and 3.

The main problem with the existing system is the interpreta-tion and subjective nature of the word “major”. Specialists incorporate many individual factors into using the word. Future research should focus on the development of a system tied to more objective analysis.