The Dark Knight came to the BBFC for classification in 2008, with a distributor request for a 12A age rating. The previous film in the superhero series, Batman Begins (also starring Christian Bale and directed by Christopher Nolan), was classified 12A in 2005. In the USA, the MPAA had already rated the film PG-13, for ‘for intense sequences of violence and some menace’.

Before the film was even submitted, it attracted significant media attention, much of it due to the sudden death of actor Heath Ledger, who played The Joker.

The main classification issues in The Dark Knight are violence and threat. BBFC Guidelines for 12A at the time stated ‘Violence must not dwell on detail. There should be no emphasis on injuries and blood’ and ‘Sustained moderate threat and menace are permitted. Occasional gory moments only. The examiners who classified the film agreed it met the Guidelines criteria, however, there were a significant numbers of complaints about the 12A rating from members of the public.  

The violence in the film is quickly edited, and whilst sometimes crunchy, it is almost entirely lacking in any blood or injury details. The impacts of blows are mostly masked by actors’ bodies or camera angles, but the impression of violence is occasionally strong. For example, in one key sequence (the 'pencil trick scene'), The Joker demonstrates a 'trick' by balancing a pencil on the table; a villain’s head is then slammed onto the table and the pencil has 'disappeared'. Audiences are left with the impression that the pencil has been slammed into the face or eye of the victim, but there is no actual sight of any impact, nor any blood or injury. The action is swift and not dwelt upon, and is designed to demonstrate the completely ruthless nature of The Joker. However, a number of people complained to the BBFC about this scene claiming to have actually seen the pencil entering the man’s eye. This is not the case, but highlights a potential classification issue of the power of suggested, rather than explicit, violence, in that the tone and impression of a film is sometimes stronger than the actual details on screen. Nevertheless, the BBFC judged the clear fantasy action context and audience familiarity with the superhero genre as sufficient mitigation against the film's sometimes dark tone, hence it was rated 12A.

The threat in the film is most frequently seen when The Joker wields his preferred weapon, a knife: in one scene, he plays with the knife inside the mouth of a thug, and in another he presses it close to the heroine’s face. The Joker's slow, menacing descriptions of how he got the knife scars on his face add a significant edge of terrorisation to these threatening scenes. Public concern – then as now - over the issue of knife crime and gang violence was particularly high, due to prominent media coverage of teenagers in UK cities dying from knife attacks.

The BBFC always consider public sensibilities surrounding violence, and particularly that involving knives, especially in works aimed at a young audience, or with a significant appeal for young teenagers. However, the BBFC also takes a proportionate approach to classification, and the context of a violent scene is always critical. In The Dark Knight, The Joker is a psychotic, deranged character, as is clear from the cartoon comic strips in which he originally appeared. He is shown to be a volatile villain and the knife threat is one aspect of his unpredictable behaviour. Examiners were clear to establish that there is no undue focus on the weapon, and that it lacks any glamorous appeal (such as the knives wielded by Lara Croft in the first Tomb Raider film, sight of which was reduced to achieve a 12 classification in 2001). The presentation of knives in The Dark Knight was therefore judged to be acceptable within the 12A Guidelines, which stated that ‘Easily accessible weapons should not be glamorised’.

The BBFC recognised that the film was potentially a fairly intense experience at times; director Christopher Nolan elected to give his Batman films a brooding and gritty edge, compared to earlier Batman films, which contained more clearly comedic elements. Heath Ledger’s Oscar-winning performance as The Joker, plus his untimely death, also added to the general sense of darkness in the film, as did the more 'mature' narrative themes of vigilantism, summary justice and the compromise of civil liberties.

However, despite The Dark Knight not being a simplistic ‘good vs evil’ battle, the BBFC felt that the tone and themes could be accommodated within Guidelines at 12A, and was suitable for young adolescents. The BBFCinsight at the time noted that the film contained ‘violence and sustained threat’. A longer version of the BBFCinsight provided additional advice for parents thinking of taking their children to see the film.

When released, the film was a huge commercial and critical success.  However, there was also criticism of the decision to classify the film at 12A. Several high profile figures condemned the BBFC for passing material at a category which allowed young children to see the film. Newspaper columnist Allison Pearson and former Conservative Party leader Iain Duncan Smith complained publicly that the film was too strong for their children. There was also some wider condemnation of the BBFC, its policies and its role.

The BBFC received 364 complaints from members of the public in 2008 about ‘The Dark Knight’. In the general, the complainants felt the film was too dark and too violent for children. The bleak tone of the film, the 'adult' nature of some of its themes and the 'unhappy' ending were cited as not suitable for a film rated 12A, to which under-12 year olds could be taken, if accompanied by an adult. There were also concerns expressed that the knife threat in the film was inappropriate and insensitive in the current climate, and could encourage copycat attacks. A number of people found the facial injuries sustained by the Harvey 'Two-Face' Dent character were too gory and scary for young children. However, his wounds are clearly unrealistic and exaggerated special effects, and similar to other disfigurements found in The Mummy films (also classified 12). The death of the film's heroine, arguably the film's only sympathetic character, was unexpected and felt to be too disturbing for a 12A fantasy film. Many argued that the film should have been classified 15. There were even some calls for The Dark Knight to be classified 18, which would have restricted it to adults only.

In a typical year, the BBFC receives around 450 complaints in total, and so The Dark Knight comprising 42% of all complaints for 2008 was exceptionally high for a single film.  An analysis of this public response revealed that less than 10 per cent of those who complained about the film's suitability for children did actually take children to see the film. It was also clear from a number of letters and emails that many of the complainants were responding to press coverage of the decision, and had not seen the film themselves. It was noted that the majority of complaints were received in the same week that The Daily Mail ran a campaign lasting three days against the decision. Once media interest ceased, the complaints also significantly declined, although the film continued to be screened nationwide.

However, the BBFC did respond to the unusually high level of feedback about The Dark Knight. The film was included as a sample work in the Guidelines consultation which was taking place at the time. The BBFC regularly reviews its Guidelines every four to five years through extensive consultation with the public. Groups were asked to view the film and invited to comment about its classification. Despite being the most complained about classification decision in 2008, 69% of respondents in the consultation who had seen the film supported the 12A decision. (30% thought it too low, 1% too high). The survey also revealed 74% of respondents understood that the 12A certificate did not necessarily indicate that the film would be suitable for under-12s. Nevertheless, reaction to The Dark Knight did feed into discussions about the importance of tone as a classification issue. The consultation recognised that the tone of a film could still be disturbing even though there was very little visual detail. The use of a 'fantasy' setting was felt to be not always a sufficiently strong enough mitigation for some types of action violence or threat. The way a film made audiences feel - for example, 'creepy' or 'on edge' - was also discussed.  

These comments were fed into the revised Guidelines - published in 2009 - and helped consolidate the BBFC's position when considering 'tone' as a classification issue. The issue of the tonal aspects of a work is now directly addressed by the Guidelines.