In the UK, there has been considerable controversy about whether street gangs exist. Just over ten years ago, Pitts (2007, 2008) published the first of what has become a wave of UK gang studies (Densley 2013; Deuchar 2009; Harding, 2014, McLean, 2019) that have marked a growth in interest in the nature of gangs (Andell, 2019). Early debates focused upon whether gangs were a social construction based upon media portrayals of young people, particularly young black people, in negative ways (Hallsworth, 2013; Hallsworth and Young, 2008) or whether there were a response to inner city poverty and structural disadvantage (Pitts, 2008, 2012, 2016). The analysis in this chapter utilizes Merton’s (1948) conception of the self-fulfilling prophecy, exhorting an expansion of the analytical scope regarding the understanding of the youth gang phenomenon as an evolving entity, particularly narratives framing the understanding of an evolution from expressive to instrumental gang action (Whittaker et al., 2019). It is argued that the evolution of the youth gang phenomenon in contemporary western representation and understanding exemplifies what scholars mean when they talk about a self-fulfilling prophecy (Merton, 1948)—denoting how what is fictive becomes reality.