LONDON (Thomson Reuters Foundation) - The contentious practice of gay conversion therapy will be in the spotlight at the British spin-off of the Sundance Film Festival on Saturday, a move welcomed by gay rights activists.

The film “The Miseducation of Cameron Post” tells the story of a teenage girl in the United States caught kissing a female friend after prom and sent to a Christian-inspired gay conversion camp to change her sexuality.

The movie, which stars actress Chloe Grace Moretz, won the U.S. Grand Jury Prize when it was shown at the Utah-based Sundance Film Festival in January.

Leading LGBT rights charity, Stonewall, said such a film can play an important role in raising awareness of the damaging impact that conversion therapy that can include psychoanalysis, injections and electric shocks to “cure” gay people.

“Any form of ‘therapy’ that attempts to change someone’s sexual orientation and or gender identity is unethical and wrong,” said Paul Twocock, director of campaigns at Stonewall.

“Lesbian, gay, bi and trans people are not ill.”

Despite global gains in lesbian, gay, bisexual and transgender (LGBT) rights, many gay people are still forced to undergo therapy based on the idea that homosexuality is a mental disorder or medical condition.

While the practice has been widely discredited, only Brazil, Ecuador and Malta have nationwide bans, says the International Lesbian, Gay, Bisexual, Trans and Intersex Association.

The film, based on a novel by U.S. author Emily Danforth, depicts Moretz’s character undergoing counseling and exercise classes at the camp where a conservative therapist persuades her to use her faith to banish her homosexual feelings.

Bisi Alimi, an LGBT rights campaigner who spent seven days confined in a church in Nigeria as a teenager after being advised to go by friends when he expressed gay feelings, said the film highlighted an issue rarely discussed.

“It was a process of being told that who I am is filthy and bad and I needed God to help me,” London-based Alimi told the Thomson Reuters Foundation.

“Gay conversion therapy doesn’t work, sexuality is natural.”

Alimi, like the fictional characters in the film, attempted suicide three weeks after he left the facility but now accepts himself after coming out on Nigerian television in 2004.

Despite welcoming the presence of the film at Sundance, Mike Davidson, head of the Christian charity Core Issues Trust, said not enough space in the film industry was given to unpopular perspectives that show how the therapy can appeal to some.

“We work to support men and women who want to move away from homosexual practices and we think it’s really important to defend their right and freedom to do that,” he said.

Davidson sees about 20 clients a week in person and on Skype and says a ban would push people underground to seek treatment.

“Nobody has to agree with us but surely we all have to come around the table,” he said.

As the film ends, Moretz finally tells her cohort “I’m tired of feeling disgusted with myself,” before fleeing to a nearby forest and hitchhiking on the open road towards a new future.