Recent chaos on the Central line has been well documented, with this paper highlighting the signal problems that led to massive stoppages, slow trains and schedules thrown off gear on the Central Line on Monday.

One family alleged that their kin was killed while walking on the tracks that day. While that account has been disputed,  the point of this edit is that surging crowds, panic, confusion and fear lead to a combustible, dangerous situation, with a spark needed for the powder keg to ignite in times like these.