 A scene set in South Africa was filmed in Gibraltar.The film, whose filming was carried out in close co-operation with London Underground, has been the cause of controversy due to the plot of the film involving a character seeking someone to commit suicide by diving under his train.Before the film was released, the train drivers' union, ASLEF, called the plot "insulting and foolish" despite not having seen the film and have pointed out that train drivers who experience such incidents find them "life-changing traumas".