“Give me the child till the age of seven and I will show you the man.” This pithy Jesuit line sums up official views on prevention (with a possible revision upwards to the early teens). If children are brought up well we can prevent them making bad choices and becoming problem adults. Problems cost big money to fix so investing small sums in prevention seems to make sense. It sounds lovely, but does it work? I think it can, but I know it often doesn’t. If we want to make prevention work I think we need to ensure the following: