Many of the child sex abuse scandals that have shocked Britain in recent years involve victims who were supposed to be under the protection of the state. Each year the government loses track of around 2,000 vulnerable children in care, even as reports of human trafficking inside the country are on the rise. Children ... just go missing, and we don't know what's happening to them," says John Hemming, a Liberal Democrat in Parliament. Hemming believes that better tracking of children who leave care might have made a difference in Rotherham and another abuse case, in Rochdale. In 2012 ... abusers were brought to justice in Rochdale over a child sex ring that went ignored for years despite victims repeatedly seeking local authorities' help. "[This] is all about abuse of power by employees of the state," says Hemming. "The fact that it involves the maltreatment of children for sexual gratification makes this all the worse." Jon Bird, operations manager at London's National Association of Adults Abused in Childhood, says nearly half of the survivors ... of human trafficking were at one time inside the U.K.'s care system. The U.K.'s Human Trafficking Centre's latest assessment shows a total of 2,744 people, including 602 children, reported as trafficked for exploitation in the U.K. in 2013, up 22 percent from 2012. Victims were forced to work in brothels, hotels, private homes or on the street as sex workers, and also forced into domestic servitude or to work on building sites or in farms and factories. The government-run National Crime Agency declined to discuss potential links between the child-care system and trafficking.