Child runaways are in grave danger because mobile phones and social networking sites leave them vulnerable to predators, a new report has warned.
The Children's Society report, titled Make Runaways Safe, revealed that pre-teens as young as eight are now among those at risk of serious harm, physical abuse or sexual exploitation.
Many are being actively targeted by adults in public places including parks and bus stations - and increasingly by their peers. And in a quarter of cases they are forced to leave their homes, often fleeing violence and abuse, it said.
Recent figures compiled by the charity showed more than 100,000 youngsters run away every year - roughly one every five minutes. According to the figures, two-thirds of cases go unreported.
Chief executive Bob Reitemeier branded the cost to children and society "unacceptable".
He said: "Society is failing young runaways, condemning tens of thousands of children to misery and danger by failing to provide an adequate safety net to break their fall.
"We call on the government to urgently put a national action plan in place. The charity is calling for a national safety net to be put in place for every child who runs away."
Currently one in six end up sleeping rough; one in eight resort to begging or stealing to survive and one in 12 are hurt or harmed. Only 5% will seek professional assistance while they are away.
The average age of runaways is also falling, the report said. Where previously this was between 13 and 14, the charity is now working with growing numbers of 11- and 12-year-olds and increasing numbers of boys.
Some 80% do not seek help because they do not know where to turn or they fear the consequences, Mr Reitemeier said.