Gangs have risen and fallen. They’ve moved from gambling into clubs and protection, smuggling and prostitution, clubs and protection. Today they make millions from full-scale drug importation. But is there a pattern to their criminality? In this programme Gary and Martin recap their experiences across the country to examine and compare gangs past and present. They pose big questions to top experts - why do we have gangs? How do they make their money? How do they hold on to it? What has been done to try and break them? Are the same circumstances that gave rise to the gangs over a century ago still with us now and, perhaps most importantly of all, can we learn from the past to counter the gangs of the future?