(CNN)For months, someone was trying to change Andy Taylor's sexuality. He just didn't know it.
"I had no idea what was going on," Taylor recalled, thinking back to a series of unnerving one-on-one meetings with a church leader in Liverpool, England, in 2012. "Even after I quit, I didn't fully realize that what I went to was conversion therapy."
But he was sure of one thing: "I just knew I didn't like it."
Taylor, an openly gay man in his early 20s, had been involved with a local church whose leaders had encouraged him to take therapy sessions. Unbeknownst to him until he stepped inside, the sessions were intended to make him believe that he was straight.
These so-called conversion therapies, also known as reparative treatments, rely on the assumption that sexual orientation can be changed or "cured" -- an idea debunked and discredited by major medical associations in the UK, the United States and elsewhere.
During his meetings, Taylor says, he was asked to recount childhood traumas and to discuss in detail his sexual experiences with men. "They knew what outcome they wanted... They looked for big emotional buttons to press, and they would just pick at them until I started crying," he said. Those events and insecurities were then connected to his sexual attractions.
"When was the first time you saw your mother cry?" Taylor recalls being asked before having his answers maneuvered toward a pseudo-psychological conclusion. "You have an overabundance of compassion, and you interpret that to mean you're sexually attracted to men," he was told.
"It makes absolutely no sense, but at the time, it seemed totally logical," Taylor said, and it led him to the seemingly natural conclusion that his sexuality "was bad" -- and that he had ought to resist it.
"It came from someone I trusted," he said. "I had no reason not to believe him."
That trust persevered even as Taylor's mental state didn't. He began having thoughts about self-harm and vivid dreams about suicide, falling into a period of depression. "I went to three or four sessions before it started to disturb me."
Eventually, he started to question the logic behind the sessions. "I'm pushing myself towards this goal which makes me incredibly uncomfortable, and the journey makes me feel horrific," he remembered thinking.
"It just felt so wrong. It felt like someone twisting a knife in me."
About six months after his first meeting, while signing into another, he realized that he couldn't continue.
"Looking back, it's one of the most manipulative things anyone's ever done to me," he remembered.
Taylor's experience is jarring, but it isn't uncommon.
Studies have found that efforts to change a young person's sexuality can put them at a greater risk of depression or suicide. Despite being condemned by medical bodies and having its science debunked by experts worldwide, the practice is legal throughout most of Europe, where campaigns and petitions to halt it exist in several countries.
In the shadows
One in 20 LGBT people in the UK has been offered conversion therapy, and an additional 2% have taken part in it, according to a survey of over 100,000 people by the UK government in 2017.
"Tens of thousands of people said they had been offered some form of [conversion] therapy," a government spokeswoman said in a statement to CNN. "It is shocking to hear people are being exploited in this way after opening up about their sexuality or gender identity."
But she added that the therapy represents "a complex set of issues with lots of grey areas" - namely, that unlike the military-style camps in the United States, the practice often occurs in the shadows across the Atlantic.
Led by the "ex-gay" movement in churches, the controversial service is offered discreetly by religious leaders and psychotherapists and sometimes not even explained to its subjects, as was the case with Taylor.
"These things aren't advertised in the phone book," he said.
Matt Ogston, 40, created a foundation campaigning for a ban on conversion therapy in 2014. That year, his partner, Naz Mahmood, had been urged to find a cure for his sexuality by his Muslim parents, who discovered the treatments online and through word of mouth.