In her recent State Opening of Parliament statement (May 2016), Her Majesty the Queen announced that action will be taken to ensure better mental health provision for individuals in the criminal justice system. We are optimistic that this welcome initiative means that all offenders, including those under 18 years old, will soon benefit from much needed and improved mental health services. Young offenders are known to have high levels of unmet and untreated mental health needs; they have frequently been in care and often come from violent and neglected backgrounds. This year's legislative programme is the opportunity to implement prevention, early intervention and treatment that suits young offenders and will improve young people's life outcomes.BACKGROUNDIn many countries, young offenders have some of the worst health of any group of young people. Deaths of young offenders are 10 times higher than in other adolescents due to drug overdose, suicide, accidental injury and homicide.1 In England, there are widespread concerns about organisational fragmentation and poor care in secure services for young people. This came to light on film at the private sector Medway centre.2 In relation to custody across all ages, the policymakers responsible for mental health have 'taken their eye off the ball': in Parliament, recently, Luciana Berger3 (Shadow Cabinet) requested information on the number of people with diagnosed mental health conditions receiving a custodial sentencing in the last five years. Jeremy Hunt (Secretary of State for Health) was unable to give an answer.Young people with mental health disorders are especially vulnerable while in custody. The board responsible for monitoring their care since 2000 (Youth Justice Board) has failed to implement good mental health practices.4Research funded by the Wellcome Trust shows there has been a gulf between well-intentioned policies on mental health in prisons and their implementation for over a century.5 Deaths of young people in custody demands effective implementation6 - this year, the whole system of youth justice is currently under review.7 In addition, young people have given their priorities through the Association for Young People's Health (AYPH). AYPH8 underlines two measures from the Public Health Outcomes Framework: reducing first time entrants to the youth justice system and reducing the suicide rate.WISHFUL THINKING?Under the Health and Social Care Act 2012,9 NHS England has the overall responsibility for health including mental health in prisons and immigration detention centres. This year, the government introduced a Five year Forward view on Mental Health.10 There is acknowledgement that half of all mental health problems are established by the age of 14 and this rises to three quarters by the age of 24. The risk factors for a mental illness are similar to the risk factors for becoming a young offender. In 2016, the National Audit Office estimates 90% of prisoners have mental health, drug and/or alcohol problems.11 The limited evidence we have from youth justice suggests this could be true for young offenders,12 who may have similar levels of unmet mental health needs. This could be aggravated by high levels of traumatic brain injury, recently estimated to be between 49% and 72% in young offenders.13 A risk factor for childhood traumatic brain injury is violence in the home and having come from a violent home is a risk factor for later offending. Longitudinal and inter-generational studies have shown that the more adverse events a growing child experiences, the more likely they are to develop mental disorders and antisocial behaviours. Of the sons of male prisoners, 60% are eventually imprisoned.There is insufficient provision for prevention, early intervention or continuing treatment of mental illness in young offenders. In this population, government fails to meet the UN's Sustainable Development Goals. Goal 3 is to ensure healthy lives and to promote wellbeing for all at all ages. …