British Board of Film Classification

The British Board of Film Classification, otherwise know as the BBFC is the company whom classifies and censors every film before they are released in England to make sure that only the intended people can watch/purchase it.
 
Universal: Anybody can purchase and watch a film rated 'U'. There is going to be next to no unsuitable material for children aged 4 years or over in this movie.

Parental Guidance: This means the film is suitable for anyone. The film should not be disturbing for anyone over the age of 8 years old. It may include mild language and sex/drug references. May contain moderate violence (such as fantasy violence). A parent    may was to check the content before letting their child watch it.

12A: This only applies to cinema's across England. The content in the film may contain mature themes, discrimination, soft drugs, moderate language, moderate violence, sex references and nudity. Sexual activity may be briefly and discreetly portrayed. Use of strong language may be permitted based on frequency and how they are used, as well as contextual justification. Sexual violence may be implied or briefly indicated. Because of this the film is most likely to be unsuitable for children under the age of 12 so they have to be accompanied by an adult in order to be able to watch the film at the cinema.

12: Suitable for people aged 12 or older. It's illegal to supply a film with a 12 certificate to someone under the age of 12. 12-A rated films usually get 12 certificates for the DVD version of the film. The content guidelines are the same as the 12-A certificate.

15: Suitable for people aged 15 and older. No one younger than 15 may see a 15 film in a cinema. It is illegal to supply a film with a 15 certificate to anyone under that age.
Films under this category can contain adult themes, hard drugs, (frequent) strong language, strong violence and strong sex references, and nudity without graphic detail.

18: Suitable only for people aged 18 or older, which means adults only. No one younger than 18 may see an 18 film in a cinema. It is illegal to supply a film with an 18 certificate to anyone under that age. Films with an 18 certificate do not have a limitation on the foul language, violence or drug/sex content. However anything too excessive may be cut such as extreme quantity of sexual violence and too much sexual content may be categorized under 'Restricted 18'.

  Restricted 18: Films with restricted 18 certificate can only be shown at licensed adult cinemas or sold at licensed sex shops. It can only be supplied to adults, and is illegal to supply through a mail order.