A Scotland Yard inquiry identified a picture of ethnically-based crime that is growing in areas where policing is often difficult and dangerous. Yardies are generally single Jamaican males between 18 and 35 years of age. They are usually unemployed, although some claim to be involved in the music business. Yardies usually assume false identities and carry forged credentials. Many have criminal convictions or are wanted by the police. Because they are known only by their street names to their associates, they are extremely difficult to identify. The United Kingdom became an attractive destination for Yardies because of the country's longstanding association with former colonies in the Caribbean. Once in the United Kingdom, the Yardies assimilate into the community and usually become involved in drug-related crime. The traditional use of marijuana has given way to cocaine and crack cocaine use. Jamaican crime groups have relatively small organizational structures. Occasional conflicts between groups are manifested in street violence but, for the most part, groups support each other. The British police response to Jamaican crime groups includes the use of immigration officers experienced in Afro-Caribbean affairs to determine true identities, along with planning and intelligence that takes into account the mobility of Jamaican criminals. 1 footnote.