A Chinese artist and a gay policeman have launched an unusually bold public protest campaign in which bright-red trucks bearing slogans denouncing homosexual "conversion therapy" are being paraded through several major cities. Artist Wu Qiong said the rolling protest was inspired by the 2017 film "Three Billboards Outside Ebbing, Missouri", in which Frances McDormand gave an Oscar-winning performance as a woman who uses billboards to call attention to her daughter's unsolved rape and murder. "'Three Billboards' was about raising and questioning unresolved issues. We wanted to also use this format to raise doubts (about conversion therapy)," Wu, 28, told AFP. Wu, who is based in the southern city of Shenzhen and says he is not gay, adds that the campaign will be staged in eight cities. It began last weekend in Shanghai. His policeman associate declines to reveal his name. China removed homosexuality and bisexuality from an official list of "mental illnesses" in 2001, but official terminology still includes vague references to "sexual orientation disorders". Some parents are known to pressure gay children to "correct" their orientation, including through conversion therapy. The trucks bear slogans saying the therapy was being used on a "non-existent disease". Others say: "'Chinese Classification of Mental Disorders' still includes 'sexual orientation disorder'", and "It's been 19 years, why?" The method is widely considered bogus, and in 2017, a court in central China ordered a psychiatric hospital to compensate a gay man who was forced to undergo conversion therapy. But many Chinese clinics still offer it. "Treatment" has reportedly included electroshocks, confinement, threats of violence, and pressuring patients to take unidentified medications. - Softening opposition - The first trucks toured around Shanghai last Saturday before the campaign moved to nearby Nanjing on Monday. An appearance in Beijing is planned later. Separate vehicles are hired in each location due to restrictions on inter-city trucking. Such campaigns are rare in China, where authorities quickly shut down most public protests to prevent them from snowballing. But Wu said the project has encountered no obstructions yet. Its Chinese social media hashtag remains unblocked by censors and had six million views as of Wednesday. Many gay Chinese report softening social opposition to homosexuality, but authorities still routinely block gay-themed events. Activists complain of a hardening government line amid a broader campaign to purge social media and entertainment content deemed "unwholesome". "The space for public opinion on LGBT-related topics in China is getting smaller and smaller. We want to... become a channel to connect with the public," Wu said. Wu said the project has raised about 20,000 yuan ($3,000) in donations. He hopes to raise triple that to pay for drivers and fuel. "Our ultimate goal is for more people to talk about this," said Wu. The reception in Nanjing this week has been "quite inclusive", he added. "We stopped near a shopping mall and a security guard came out to ask what 'sexual orientation disorder' meant. After we explained it to him, he supported us."