The NHS Institute has published an engagement resource. They state that it is for all commissioners of health services and sets out what is required when engaging patients carers and the public in decisions about health service provision.
They note that one of the many reasons for engagement is a legal reason in light of the statutory duty on CCGs. This is of course in addition to the moral business social political and health reasons.
http://www.institute.nhs.uk/tools/the_engagement_cycle/the_engagement_cycle_introduction.html