Question: You've called for new interventions to stop early behavioural problems in young children - what form should that take?

OLIVER LETWIN: We don't yet fully know the answer to that question. 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 are already showing signs of significant behavioural problems.

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

We are also 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.

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.

We are also clear that there are some kinds of voluntary activity, for example 'Kids Company', which I'll be visiting this week, and many others like it, which do provide some kind of stable help for children, especially where they also link back to the parents. So we have some inkling of the models that might begin to work.

We also have a structural example in the United States of the 'Headstart' programme which mobilises not just state resources but voluntary resources to try and find a range of different kinds of intervention.

And I think we are all at an experimental stage. Nobody knows the full answer to this question. But where I'm clear is that we need to experiment much more widely and much more adventurously in order to find the things that really do work before the crisis gets to be of unmanageable proportions.

Question: The traditional Conservative view may have been that badly behaved children are the proper concern of the adults responsible for them rather than a matter for the state. What do you think?

OLIVER LETWIN: I still think that is absolutely true to say, that is if we take so-to-speak the normal family, with a parent or parents who are fine upstanding people, able to look after themselves, employed and with plenty of emotional and physical energy to devote to the child or children. Far better that the state should wholly leave that to the parent or parents.

But the sad truth is that if you go the projects where people are trying to intervene and help, the overwhelming typical pattern, 80 or 90 per cent of the cases, are those in which that doesn't happen.

We're talking in many cases of parents who are either emotionally disturbed, are breaking up, have broken up, are unemployed or are likely to be so, or are who have other problem children that they have difficulties with, or on drugs, or where there is a step-parent who is wholly unsuitable. Or any number of other mixtures and circumstance which mean that the ordinary support that children get from their parents as they grow up is simply missing.

Question: Even with problem families, if the state or proxies in the voluntary sector get more and more involved in issues of childrearing what message do you send on parental responsibility?

OLIVER LETWIN: I understand that concern. But I have to say that 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. And that is of course the most gross invasion you can engage in. Now, in some cases, alas, where there is abuse for example, where there is a child protection issue, it may be the only course of action that anybody knows how to take. But 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 fulfil.

Question: Should parents be allowed to smack their children to correct behavioural problems?

OLIVER LETWIN: I certainly have absolutely no plans whatsoever to stop parents doing the things that parents can do at the moment.

The cuff round the ear from an otherwise well ordered parent who gets rather cross is a perfectly ordinary activity in the course of ordinary family life, in my view.

I have to say that in the case of the children that we are talking about, that is an order of magnitude different, from the kinds of problems that we are dealing with.

What we're dealing when you talk about behavioural problems with children are cases in which there really serious emotional problems which, as I say, lead horribly often to anti-social behaviour in later life.

Question: There has been some stigmatising by press and politicians of children and their parents, can this end up damaging the lives of vulnerable people?

OLIVER LETWIN: Not by me. I have not wandered around saying that we're dealing with people who ought to be stigmatised. I'm getting some criticism, indeed, from those who think I ought to be stigmatising them more. What I'm saying is let's stop making so many judgments about the children concerned and try to achieve an effect that is socially hugely desirable.

That is to say, to prevent vulnerable people, old people, other young people, in many cases living in the less pleasant parts of Britain being attacked or robbed by wild children, who simply haven't been given the support, the education and training, and the moral encouragement which is required to make them law abiding members of society.

Question: There has been concern that the government's recent approach to parents of badly behaved children has been authoritarian. What do you think?

OLIVER LETWIN: I think there is a worrying general tendency on the part of this government which takes two forms. One is to leap for initiatives. For example, the suggestion that suddenly child benefit would be removed from parents of children who were truanting is an interesting example of an ill-formed initiative.

I suspect by the time we are finished we will find this like many, many others of the 55 initiatives we've had from the Home Office since Mr Blunkett took control, will disappear into the sand and there will never actually be any action. So one problem is 'initiativitis'.

Another problem is, that in a desperate effort to persuade the British public that it is not soft, I think the government quite often uses rhetoric that isn't matched by delivery. And that is dangerous because it disillusions people. What I want isn't tough talking followed by soft action but sensible talking followed by effective action.

Question: Iain Duncan Smith says "trust the people" - can the institution of the family be damaged by linking the crime debate to children and parents?

OLIVER LETWIN: Not if it is properly handled. As I say the crux here is to move away from the image of a bureaucracy, imposed upon the situation, taking the children out and putting them in local authority care. All that I want to get away from. And move instead to the state facilitating community and voluntary effort to support parents, as well as children, and, as I say, to allow the family to recapture the role which we want it to perform and which it alone can really perform well.

Question: A previous high-profile Conservative initiative included a right of self defence for a home owner who killed a teenage burglar, now you talk about giving similar juvenile offenders a helping hand off the crime conveyor - what prompted the U-turn?

OLIVER LETWIN: We are talking about completely different ends of the spectrum. I shall also be investigating the question of what we do with the serious persistent criminal youth offender, that is a very serious problem alone, and demands very serious treatment.

I'm in no way suggesting that we should look at somebody who has murdered, or manslaughter or robbery or any other serious crime and just say 'oh dear this person needs support'. The need there is for deterrence, punishment and indeed re-education and rehabilitation.

That is a separate issue. I'm talking here about children at the age of five who haven't yet done anything to anybody that would register as a crime and may not even yet have engaged in any consciously aggressive anti-social behaviour.

It is the child who wanders into the classroom, and the first day the primary school teacher looks at that child, and says this is a child with a problem. The problem we've got as a society, is having said this, and I have talked to primary school teachers who will tell you this, nothing then happens. Society just waits until there is a different kind of problem and that child is throwing bricks through the window or has joined a gang and is beginning to rob people. And that's what we must not let happen - we must act earlier.

Question: Is there any danger that a disproportionate or irrational response to public fears over crime could damage civic culture?

OLIVER LETWIN: There are always dangers and that's why we have to be sure that the interventions we make are carefully controlled and not excessive.

It's one of the problems I have, for example, with the business of taking people into care, that I think it can damage the frame of civic life. Also it is one of the reasons why I very much favour voluntary activity, communal activity rather than bureaucratic activity because that helps sustain the neighbourly society I'm talking about rather than eroding it.

Question: The Guardian recently described you as "liberal, rational, self-deprecating, patently decent and brimming with optimism" - words they haven't used about a Labour home affairs frontbencher, in or out of opposition, for a long time. Are you a new Tory breed?

OLIVER LETWIN: It partly means that newspapers praise you one day and the next day damn you. And one lives with this fact and I don't pay very much attention to either the praise or the damning. I know that it is the business of the newspapers to overdo both the praise and the blame.

I think there a strange situation at the moment in one respect. Which is that the left, in the sense of the centre-left, the current government, has decided for one reason or another, best known to itself to become a very 'big brother left'. We see this in things like the effort to give powers to an enormous range of government bodies to snoop on your emails. We saw this in some of the clauses of the anti terrorism act, which contained some good things but also some bad things. We see it in the effort of the home secretary to run every police force in Britain from a desk in Whitehall.

Under these circumstances the reassertion of the traditional role of the centre right to protect fundamental liberties is, I think, extremely important. And the paradox is that there are many people who had seen themselves as in some way or another associated with the moderate left, who actually sympathise more with the protection of fundamental liberties than with Labour's big brother theme.

I hope and I expect that we will see some degree of realignment in British politics as people come to realise that today's debate is not about free markets versus socialist economics, because the free market has won that struggle.

Question: But are you in danger of alienating your Daily Mail "heartlands"?

OLIVER LETWIN: I think that the people that I talk to who must be the heartland of the heartland, mainly Tory activists, very well understand the sort of things I have just been saying now. That the child becomes the man, that the way somebody is brought up matters, that attending to that is important.

In other words the Tory activists I deal with are not horrible, heathen, thuggish people, they are just not like that. They are actually people who have children and grandchildren and they don't want us to be horrible and thuggish.

I don't think they were any more enthusiastic about the idea of the Tory party being portrayed, I think wrongly, as thuggish than the wider voting public was. That was a misperception of us and all I'm actually doing is trying to correct that misperception.

Question: In the last five years have we become a more or less tolerant society?

OLIVER LETWIN: The probable answer is neither. I think that at root the people of Britain, the overwhelming majority of people in Britain are tolerant and humane but also concerned that their way of life, which they find attractive, should be preserved. These are both reasonable and balanced sentiments. I think that most people in Britain want law and order - they want the government to make sure that the streets are safe, which they are not getting at the moment and they want the freedom to act out their own lives. So people don't come in ludicrous caricatures, I think that our society is reasonably balanced and the duty of government is to reflect that balance.