We define a child as anyone who has not yet reached their 18th birthday. This is in line with the United Nations Convention on the Rights of the Child and civil legislation in England and Wales.
Ok, thanks for the link (and the text of your post is in fact a quote for that page); but the page in question is from the UK department of justice. In the judicial system it makes sense to call all minors "children".
In an article for the general public, the use of the term is disingenuous IMHO, because people usually don't think of 17-year-old persons as "children".
In an article for the general public, the use of the term is disingenuous IMHO, because people usually don't think of 17-year-old persons as "children".