X certificate was an old BBFC rating that stated that persons under 16 could not see a film with this rating under any circumstance. The age restriction was modified to 18 in compliance with the new AA certificate in 1970, and was changed to the 18 certificate in 1982. It is the successor to the non-compulsory H certificate. However, in the 1980s, some older films, due to the BBFC being more liberal today then they were in the 1950s, have been rerated at 15, PG, or even at U. These include numerous B-movie violent films, including the "big bug" movies of the 1950s, Rebel Without a Cause, among other films.