The British Board of Film Classifications are as follows:
Suitable for all. A U film should be suitable for audiences aged four years and over.
Parental Guidance. General viewing, but some scenes may be unsuitable for young children.
Films classified 12A contain material that is not generally suitable for children aged under 12. No one younger than 12 may see a 12A film in a cinema unless accompanied by an adult.
No one younger than 15 may see a 15 film in a cinema.
No one younger than 18 may see an 18 film in a cinema.