Three Chinese men have launched a public campaign sending bright red trucks with slogans denouncing homosexual “conversion therapy” through major cities in China, in a rare public protest against homophobia.

Artist Wu Qiong said the protest was inspired by the 2017 film “Three Billboards Outside Ebbing, Missouri,” in which a woman uses billboards to draw attention to her daughter’s unsolved rape and murder.

The three trucks – the brainchild of Mr Wu, gay policeman Lin He and art curator Zheng Hongbin – are protesting “treatment” clinics that claim to turn people straight.

It also aims to build awareness with China’s 1.4 billion people that “homosexuality is not a disease,” Mr Wu, who is straight, told the Telegraph.

Being gay is not a crime in China, but Mr Wu and rights experts say there remains a lack of public understanding. Part of that stems from inconsistent official terminology – in 2001, the Chinese Society of Psychiatry removed homosexuality from a list of mental disorders, though vague references remain to “sexual orientation disorder.”

Many public hospitals and private clinics in China offer “conversion” treatments, which can include arbitrary confinement, forced medication and even electroshock therapy, according to Human Rights Watch, an advocacy group, which has called on Beijing to ban the practice.

The crowd-funded truck campaign is making stops at these “treatment” centres; Mr Wu estimates there are roughly 100 in the country.

They started rolling around the streets of Shanghai last week and will hit another seven cities, including Beijing, on a 1,860-mile nationwide road trip. One truck reads, “To cure a ‘disease’ that does not exist?”

A second says, “The diagnostic criteria for mental disorders in China still retain ‘sexual orientation disorder.’” And a third has, “It’s been 19 years, why?” referring to the 2001 change on paper that the artists feel need to be clarified.

Social attitudes in China are slowly shifting and conversion “cures” are increasingly recognised as a sham – a court in 2017 ordered a psychiatric hospital to compensate a gay man forced to undergo such therapy.

But the country “does not have a law protecting individuals from discrimination due to sexual orientation or gender identity,” according to Human Rights Watch.

Still, such campaigns are rare in China, where authorities often quickly disband public protests over fears of widespread social unrest.

In recent years, there has also been a crackdown affecting the gay community, including a ban on gay-themed television shows, and a writer slapped with a 10-year prison sentence for penning a gay erotic novel.

But so far, the bold, red trucks have toured unopposed, and the project’s social media account, followed by nine million, has escaped censorship; Chinese state media have even covered the project.

“We are not breaking the law. It’s just three trucks driving on the road,” said Mr Zheng, 32, who is straight. “Our approach is pretty mild.”