Oliver Letwin has urged greater support for the parents of problem children.

The shadow home secretary is to make a keynote speech tackling the link between a child's early behavioural problems, problem parenting and later anti-social or criminal activity.

"What we are clear about is that there are really quite large numbers of children who appear first at school at the age of five who already showing signs of significant behavioural problems," he told this website.

"The research evidence suggests that about 80 per cent of those children, an astonishingly high proportion, will go on to show signs of much more serious antisocial behaviour, so we are clear that some form of intervention is required."

Continuing to reposition the Conservatives, Letwin told ePolitix.com that his aim was to support - not stigmatise - problem families. "I have not wandered around saying that we're dealing with people who ought to be stigmatised," he said.

But the shadow home secretary hinted that he was under some pressure to be tougher. "I'm getting some criticism, indeed from those who think I ought to be stigmatising them more," he said.

"What I'm saying is let's stop making so many judgements about the children concerned and try to achieve an effect that is socially hugely desirable."

He said the government must give young people "the support, the education and training and the moral encouragement" to make them law abiding members of society.

He warns that "vulnerable people, old people, other young people" are paying the price of failing to tackle "wild children".

Widely regarded as a liberal Conservative, Letwin's call for parenting support rather than a return to traditional family values heralds a period of policy"experimentation".

Key to tackling behavioural problems at an early age, he says, is a combined state and voluntary sector approach.

Letwin says he wants to put in place early help for parents - moving away from a social service intervention which puts children in care.

"We are clear from the research evidence that where efforts have been made to help parents do their job better those are often more successful than efforts to replace or proxy for parents," he said.

"For example, we're clear that the system of taking people into care, completely over-ruling the parents, has almost completely failed so far as crime is concerned."

Letwin says that fewer children should be taken into care - describing the practice as a "gross invasion" which sends out the wrong message on parental responsibility.

"At the moment and for many years in the past, we have been sending very much the wrong message, in the sense that when things really go wrong, if there is an intervention at all it typically takes the form of removing the child entirely from the parent or parents," he added.

"In the cases I'm talking about that would be quite the wrong kind of response. It is an effort to help both the child and the parent, and to begin to restore a sustainable relationship where the parent or parents can start to do the job that parents should be doing.

"This is not an effort to extend the nanny state, on the contrary, its an effort to help parents take back the role, which, alas, some aren't currently able to able to fulfil."