What is "appropriate adult"

n. (context UK legal English) An adult, such as a parent, guardian(,) or social worker, whose role is to safeguard the interests of young people detained by the police, and who must be present at such interviews.

Appropriate Adult is a British crime drama television mini-series and television film, first shown on ITV on September 4 and 11, 2011. The series stars Dominic West, Emily Watson and Monica Dolan as the protagonists of the story, Fred and Rose West, and Janet Leach. It is based on the true story of Gloucester serial killer Fred West and his wife Rosemary West. It focuses on the events between the Wests' arrests in 1994 and Fred's suicide in Birmingham's Winson Green Prison on New Year's Day 1995. The series was named after the role of Janet Leach as an " appropriate adult" during the questioning of Fred West. The senior investigator wanted to ensure that there could be no suggestion that West did not understand any part of the process, so arrangements were made so that he had an "appropriate adult" present to ensure this at all times.