Joker is a psychological thriller about a stand-up comedian who becomes increasingly unhinged.

The film is based on the DC Comics villain and Batman's nemesis, the Joker, but the director Todd Phillips has said that he has left purposefully unanswered the question as to whether this character is the one faced by the adult Bruce Wayne or the inspiration for a copycat.

This is a dark and sombre telling of an origins story and sees Arthur Fleck, a professional clown with a condition that means he bursts out into uncontrollable laughter at inopportune moments, spiralling out of control in 1980s Gotham.

The film had been under discussion for a number of years, with Joaquin Phoenix having expressed an interest in acting in a low-budget 'character study' type film about a comic book villain. He had previously declined to act in the Marvel Cinematic Universe because he would have been tied in to multiple films. Similarly, Phillips had been offered comic book films but had declined. According to Phillips, he was attracted to the Joker because he did not think there was a definitive portrayal of the character, which he knew would provide considerable creative freedom. Phillips and his co-writer Scott Silver began drafting the screenplay in early 2016 and Phoenix was officially attached to the project in July 2018.

A trailer for the film was submitted by Warner Brothers in March 2019, with a 12A request. Compliance Officers noted that 'There is an unsettling and dark tone throughout, and there are certain shots which would be uncomfortable at the 12A category'. They cited a scene in which Fleck smashes his head into a mirror and another in which he is hit by a car.

Compliance Managers also viewed the trailer and agreed that it would be better placed at 15. A cuts list was written for Warners and the trailer was resubmitted in an abbreviated form and given the requested 12A.

A further trailer, submitted in May 2019, also came to the BBFC with a 12A request. This was a shorter version, but contained the same scene with Fleck headbutting the mirror and was awarded a 15 rating. Other, similar trailers were also passed at 15.

The completed film was submitted for an advice viewing and was seen on July 1st 2019 by the BBFC's Chief Executive and the Head of Compliance in the screening room at Warner Brothers' London base. The film appeared to be complete.

The viewing notes stated that the film was permissible at the requested 15, with the main issue some strong and occasionally bloody violence. The strongest scene is that in which Fleck stabs a man with a pair of scissors and then bashes his head repeatedly against a wall, causing significant blood spray and the release of some brain matter. Other violence includes some men shot with bloody impact detail and a chat show host executed at close range, with blood and brain matter sprayed up the wall behind him. The scenes are strong and shocking, but do not last long and there is no focus on the victims' injuries afterwards, BBFC Guidelines at 15 state that 'Violence may be strong but should not dwell on the infliction of pain or injury'.

There is also some strong language, around 25 clear uses of the term 'f**k' and some bleeped uses in news reports. These are acceptable at 15 where Guidelines allow for strong language.

The team also noted several scenes in which Fleck thumbs through notebooks, including while performing on stage. The books contain images of naked women, presumably cut from pornographic magazines and pasted in amongst his jottings. The images are not seen in close-up and are only very fleetingly on screen.

The film was submitted for formal classification on September 24th and was passed at 15, with the insight strong bloody violence, language.

The detailed Ratings Info notes that the film contains:

'…Scenes of strong violence include stabbings and shootings, with accompanying bloody injury detail.

There is strong language ('f**k') throughout, as well as milder terms such as 'prick', 'asshole' and 'shit'.

There are some briefly glimpsed images of models posing naked.

The film was released in the UK on 4th October 2019, playing on 668 screens. It took £12.8 million in three days and went on to top the box office charts.

The film was selected to be screened as part of the 2019 Cinemagic Film Festival.