The concept of a vulnerable adult as someone meriting equivalent treatment as children/minors seems to have pervaded British policy and legal parlance. For example, most of the clarifying materials to elaborate this concept are about interviewing such individuals while they are in police custody, however, general conditions of arrest in PACE 1984 also mention this term and thus seem to employ the same concept and implicitly invoke the same definition. In other policy documents and general parlance of the British infrastructure even in informal colloquial lexicon it seems to even have become used to make moral points by lay folks.
Where did this concept originate if not first in PACE 1984?
And Are there any clear legal provisions to expand the application or applicability of the term and concept?
Finally, are there any legal provisions which explicitly gives the term a uniform definition across all its different legal and civil government usage contexts?
Note: not sure what tags may be the most appropriate for this question. Please feel free to modify/adjust. Thanks