2.1.1 When disasters occur it is rare that causation can be attributed to one single overarching act or omission. Even when there is unequivocal evidence that such a single action by an individual or individuals occurred or there was negligence, the historical context and the immediate circumstances are vital ingredients to understanding and explaining how a failure or failures in systems, and the judgements of those responsible, came together. Because systems, their design and monitoring, and their operators evolve over time they are susceptible to custom and practice. For that reason, particularly in situations where people gather in large numbers as travellers, spectators or participants, public events are regulated and managed to create the safest possible environment. That responsibility falls on the owners and, if appropriate, the hirers of the facility, on those responsible for managing and policing people before, during and after the event and on those responsible for responding effectively and efficiently to any emergency should it occur.
2.1.2 While the Panel's work focuses on a disaster involving mass fatalities, injuries and trauma, it is important that the circumstances of the Hillsborough disaster are placed in the context of previous incidents at the stadium and the lessons that were learned, or not, from debriefings and from negotiations between the owners, the safety engineers, the local authority, the police and the other emergency services. The structural condition of the stadium, including alterations to the stands and terraces, was a significant factor in establishing whether it provided a safe environment for spectators, especially when full to capacity. Given the pre-eminent climate in which soccer was policed throughout the 1970s and 1980s, the custom and practice adopted by Sheffield Wednesday Football Club (SWFC) and South Yorkshire Police (SYP) in the management and regulation of the crowd were also important factors.
2.1.3 Following the 1989 disaster considerable evidence relating to the context, circumstances and consequences of the 1981 crushing on the Leppings Lane terrace was gathered by the key agencies concerned, primarily to establish whether the tragedy was foreseeable and preventable. What follows draws significantly on that evidence as disclosed to the Panel. Not all the evidence sought has been provided, in some cases because it no longer exists.