This guideline covers both health and social care services. It aims to improve the planning and delivery of care, and young people's experience as they move from children's to adults' services. It focuses on all young people aged up to 25 who are going through a planned transition, including those who have mental health problems, are disabled or who are looked after.

Transition is defined as a purposeful and planned process of supporting young people to move from children's to adults' services (Transition: getting it right for young people Department of Health and Department for Education and Skills). But making this move can be difficult or provoke anxiety in young people and their carers.

There is a wealth of policy and guidance on agreed principles in respect of good transitional care, but there is also evidence that these principles are often not reflected in practice (for example, Beresford and Cavet [2009] Transitions to adult services by disabled young people leaving out of authority residential schools and the NHS Diabetes report Diabetes transition – assessment of current best practice and development of a future work programme to improve transition processes for young people). Without proper support, young people may not engage with services (Watson 2005, Singh 2009), leading to a loss of continuity in care. This can be disruptive for young people, particularly during adolescence when they are at a higher risk of psychosocial problems (Patten and Viner [2007] Pubertal transitions in health).

Although this guideline does not cover adolescent care more generally, it should be noted that transition from children's to adults' services takes place within the context of broader cultural and developmental changes that lead a young person into adulthood. As a result, young people may be experiencing several changes simultaneously (McDonagh and Viner [2006] Lost in transition? Between paediatric and adult services).

This guideline has been developed in the context of a complex and rapidly evolving landscape of guidance and legislation, most notably the Children and Families Act 2014 and the Care Act 2014. While the Care Act and other legislation describe what organisations must do, this guideline is focused on 'what works' in terms of how to fulfil those duties. It is relevant to young people using health and social care services, their families and carers, care providers (including independent and voluntary sector providers), health and social care practitioners and commissioners (including people who purchase their own care). It is particularly aimed at professionals and managers in health and social care services, in both children's and adults' services.

The guideline will also be relevant to all people working with young people who are receiving health and social care services, in particular those working in education and employment agencies, youth justice and housing support.