BBFC

'15'

Noone younger than 15 may see a '15' film in a cinema or rent/buy '15' rated films.
The film must not endorse discriminatory language or behaviour. Drug taking may be shown but it must not be promoted and the usage of highly dangerous or easily accessible drugs is unlikely to be acceptable. With horror, strong threat or menace is allowed unless sexualised. Dangerous behaviour should not be so detailed as to be imitated. There may be frequent use of strong language. The strongest terms may be used if justified. Aggressive or repeated use of the strongest terms may be found unacceptable. Nudity can be allowed in a sexual context if there is not much detail. Sexual activity is allowed to be portrayed as long as it doesn't contain strong detail. Strong verbal references are allowed. There is no theme, content just has to be appropriate for 15 year olds and violence can be strong but shouldn't dwell on the infliction of pain or injury.

'18'
Noone younger than 18 may watch an '18' at the cinema or rent/buy '18' rated films.
With the findings of the BBFC and The Human Rights Act 1998, the BBFC guidelines do not overrule the principle that adults should be able to choose there own entertainment so the BBFC guidelines do not really apply. There are some exceptions to this such as if the films content breaches the law or contains material which risks actual harm to individuals or strong explicit images of sexual activity which cannot be justified.