<p>In recent weeks, London has been hit by three nail bomb attacks and has once again focused public and professional attention on the management of major incidents. The harrowing scenes of trauma following the Soho bomb illustrated the importance of integrated emergency management and the need for well prepared emergency personnel and major incident plans. Organisations involved in the incident are currently holding operational debriefs in an attempt to analyse key issues and a plan for the future. One question that may be on the agenda is ‘what is the rationale for a major incident declaration?’</p>