Submarine was made in 2010 and released as a 15 in 2011.
For a film to be certified as a 15, BBFC has the following requirements and restrictions:
15 – Suitable only for 15 years and over
No one younger than 15 may see a 15 film in a cinema. No one younger than 15 may rent or buy a 15 rated video work.
The work as a whole must not endorse discriminatory language or behaviour, although there may be racist, homophobic or other discriminatory themes and language.
Drug taking may be shown but the work as a whole must not promote or encourage drug misuse (for example, through instructional detail). The misuse of easily accessible and highly dangerous substances (for example, aerosols or solvents) is unlikely to be acceptable.
Dangerous behaviour (for example, hanging, suicide and self-harming) should not dwell on detail which could be copied. Whether the depiction of easily accessible weapons is acceptable will depend on factors such as realism, context and setting.
There may be strong language. Very strong language may be permitted, depending on the manner in which it is used, who is using the language, its frequency within the work as a whole and any special contextual justification.
There are no constraints on nudity in a non-sexual or educational context. There may be nudity in a sexual context but usually without strong detail.
Sexual activity may be portrayed, but usually without strong detail. There may be strong verbal references to sexual behaviour, but the strongest references are unlikely to be acceptable unless justified by context. Works whose primary purpose is sexual arousal or stimulation are unlikely to be acceptable.
There may be strong threat and horror. A sustained focus on sadistic or sexual threat is unlikely to be acceptable.
Violence may be strong but should not dwell on the infliction of pain or injury. The strongest gory images are unlikely to be acceptable. Strong sadistic violence is also unlikely to be acceptable. There may be detailed verbal references to sexual violence but the depiction of sexual violence must be discreet and justified by context.
Sourced from the BBFC website ( http://www.bbfc.co.uk/what-classification/15 ) on 04/10/2016.
In Submarine there are over 25 uses of strong language, moderate sex references and a scene where a character swallows a handful of pills. The film becomes a 15 because it falls into three of the categories shown above – Drugs, Language and Sex. Subamarine can pass as a 15 because there isn’t severe drug use, the strong language isn’t used in an extreme context and there aren’t extreme references to sexual behavior or strong detail when sexual activity is portrayed.