“British gangs are quite unlike the Italian Mafia model or the Turkish groups,” he said. “There are no set ranks, rules and structures. They are more fluid, flexible and opportunist.”

Many foreign gangs active in Britain are based overseas and exploit the 11,000-mile coastline and security weaknesses at sea ports to smuggle drugs, guns and counterfeit goods into the country. Much of the media coverage of gangs has concentrated on turf wars and feuds, but serious criminal activity is focused on making money.