Early-onset behavioural problems such as aggression and non-compliance are the best predictors of antisocial and criminal behaviour in adolescence and Randomised controlled trial of a parenting intervention. Untreated, up to 40% of children with early difficulties develop subsequent conduct disorder, including drug misuse, criminal and violent behaviour. Early behavioural difficulties predicting long-term problems are easily identifiable and effective interventions prevent progression into more severe difficulties. There are severe financial costs if conduct disorder is not prevented. Utilisation of health, social, education and legal services is ten times higher for this population, mostly borne by publicly funded services, especially in areas of social exclusion. Parenting behaviour contributes to the establishment of conduct disorder and many children learn, develop, or establish problem behaviours because parents lack, or inconsistently use, key parenting skills9. When ineffective parenting is the problem, cognitive-behaviourally based parenting programmes can provide an effective solution but are more effective with younger children. When both child problems and parenting patterns are less well-established parents can more easily influence their children?s behaviour. One UK government strategy is Sure Start early preventive parenting support for families of pre-school children living in identified high-risk, disadvantaged areas. Since its launch in 2001 ?3.1 billion has been invested in the scheme11. This funding was provided without direction from government about which services should be delivered. As a result, widely varying services were provided, many lacking evidence of effectiveness from randomised trials.