The term "underclass" refers to more than just a societal group with low incomes. It encompasses a group of people whose behaviors, values, and attitudes conflict with those promulgated by mainstream society. Although there are many ways to identify an underclass, this essay focuses on three factors that have proven to be early warning signals in the United States: illegitimacy, violent crime, and drop-outs from the labor force. In documenting the existence of these factors in Great Britain, the author uses data collected and published by Britain's Statistical Service. Data show a sharp increase in illegitimate births in Great Britain, an increase which is concentrated in the lowest social class. There will be a difference in child-raising between a neighborhood composed mostly of single mothers and one composed mostly of two-parent families. The key to an underclass is that a large proportion of an entire community lacks fathers, and this is more common in poor communities than in more affluent ones. Regarding violence, the violent-crime rate in England and Wales has been increasing rapidly. The prevalence of violent behavior is greatest in those neighborhoods where an underclass is dominating. If illegitimate births are the leading indicator of an underclass and violent crime a proxy measure of its development, the definitive proof that an underclass has arrived is that large numbers of young, healthy, low-income males choose not to take jobs. The decrease in labor force participation is the most elusive of the trends in the growth of the British underclass. The author's suggestion for a strategy to deal with the underclass is to facilitate the capacity of underclass communities to govern themselves. This rests in the belief that no community, when left to its own devices, will tolerate crime, illegitimacy, or voluntary idleness among its youth.