The conclusions, published yesterday, are from a report by the Kids' Clubs Network, a voluntary group which organises after-school childcare. The findings are described as a "situation of unease", with children "becoming more isolated" and "tempted into crime through boredom and lack of amenities".
Most parents questioned for the report agreed the life of a latchkey child was "lonely and potentially dangerous", with one-third of all parents worried about what happened to their child after school hours.
With 70 per cent of mothers with primary-school children working, the report says that in addition to the growth of latchkey kids, a quarter of all primary-school children now go to and from school without adult supervision.
Coming after recent research on the negative effects of working parents on children's educational development, the findings are likely to add to the debate on childcare. At a conference in London yesterday to launch the latest research, Anne Longfield, the director of Kids' Clubs Network, said: "We can't on the one hand encourage parents to take up employment and training and yet ignore the lack of after-school childcare provision."
The 9 per cent figure comes from research which said 6 per cent of children were "definitely left alone" but added that the true figure, given parents who masked the situation, pushed it up to 9 per cent.
At the conference, Labour's education spokesman, David Blunkett, called for the "development of a national network of after-school clubs to ensure that all children are cared for in a safe and stimulating environment at the end of the school day". Mr Blunkett widened Tony Blair's recent call for homework centres by saying that "after-school clubs, together with after-school sport and leisure, are the antidote to the latchkey kid waiting in an empty house ..."
Although Labour has said it intends to make after-school care a priority, expanding the voluntary sector in conjunction with the Government, no specific targets or funding have yet been given.