CITIES ON THE EDGE: Safety and security are two of the biggest challenges faced by each and every metropolis. Whether earthquake, terrorism, flood or just crime, it’s the geology, politics and social makeup of the megacities that make them some of the most profitable and dangerous places to live. Andrew Marr takes a look at safety and security, visiting Tokyo, London and Mexico City.

1 x 60mins     AVID                       Ricochet / BBC 1                                  Executive Producer: Billy Paulett