The document summarizes the rating categories of the British Board of Film Classification (BBFC). It outlines the criteria for films rated "U", "PG", "12A", "15", and "18", including what level of violence, language, sexual content or other adult themes would be permitted for each rating. It then provides an example list of top thriller films from 2011 and their BBFC ratings, showing that "12A" and "15" were more common than the restricted "18" rating. The document concludes by stating a film has been rated "12" as its storyline aligns with that rating level.