“Inside my heart is breaking, my makeup may be flaking, but my smile still stays on.” When Freddie Mercury sang such lines of devastating personal collapse in “The Show Must Go On”’s video in October 1991, accompanied by archive footage of a lifetime of firebrand performances as Queen’s incomparable frontman, few fans imagined how close to home they fell. They’d seen how frail and thin he looked in the video for “These Are the Days of Our Lives” the month before, but not how he’d struggled to stand through the shoot, such was his incapacitating pain. Nor could they have known that his typically grandstanding vocal was delivered through alcoholic bravado, propped up against the microphone barely able to move. “I’ll face it with a grin,” he howled against the dying of the light, “I’m never giving in, on with the show.”

“When he came in he wasn’t in a great state,” Queen’s guitarist Brian May recalls of the song’s recording in 1990, in a new BBC documentary detailing the closing chapter of Mercury’s life, Freddie Mercury: The Final Act. “He was finding it hard to walk, even finding it hard to sit. He said, ‘Bring the vodka,’ he pours himself a shot, knocks it down and then he props himself up, knocks another vodka back and then he went for it. Those notes came out of him and I don’t know where they came from.”

Four weeks after the single’s release, and after 20 years as one of rock’s greatest and most beloved showmen and the iconic voice of “We Are the Champions”, “We Will Rock You” and “Bohemian Rhapsody”, Mercury said his goodbyes. He refused further medication and, aged just 45, retired to his Kensington home with a close coterie of friends to die. Those present for those private last two weeks – including his boyfriend Jim Hutton, former partner Joe Fanelli, his PA Peter Freestone and Dave Clarke of the Dave Clarke Five – describe carrying his fragile form downstairs to view his art collection one last time before he passed, on 24 November, 30 years ago this week. May’s wife Anita Dobson remembers him telling her: “‘Darling, when I can’t sing anymore I’ll just die, I’ll drop dead.’ When he’d sung all he could sing he withdrew and he got ready to die.”

Because the band feared press intrusion and the stigma of what was being called a “gay plague”, the nature of Mercury’s illness – HIV/AIDS, reportedly diagnosed in 1987 – was only revealed publicly 24 hours before his death. It had been a closely guarded secret within his inner circle for some time. Suspicions had gone unvoiced among his bandmates, concerned by the marks appearing on his skin, his increasingly frequent trips away for treatment and his reluctance to tour following the biggest shows of Queen’s career at Wembley Stadium and Knebworth in 1986, until he confirmed their worst fears during a brief, blunt meeting in Montreux.

“We’d done the biggest tour of our lives and it was a great success and we were very happy, and Freddie said, ‘I can’t do this anymore,’” May explains in the doc. “We saw him disappearing and coming back with these burns to his skin. We didn’t like to ask because we didn’t want to know perhaps, and that went on a hell of a long time… Freddie at that time was still full of energy but [there were] signs that something was attacking him. We wanted to think it was something else. Maybe to do with his liver or something. There was a certain amount of self-deception going on. In the end it became fairly obvious.”

With Mercury insisting he wanted to keep making music (Queen completed their 1991 album Innuendo and laid the foundations of 1995’s posthumous Made in Heaven while Mercury battled his illness), the group agreed to mislead the press to protect their friend. “I was absolutely prepared to lie through my teeth right up to the last minute,” says drummer Roger Taylor. “He didn’t want to go through the misery of being the object of pity or scrutiny when you’re that sick. So he did announce it and within 24 hours he was gone. I thought that was probably perfect timing.”

“I imagine when there is an inevitability of something approaching there does come an acceptance of its arrival, and one would want to approach that in as accepting a way as possible,” says the documentary’s producer Dan Hall of Mercury’s final days. “And so the sense of shutting down, socially as well, just gradually closing down, makes absolute sense.”

“He said he said goodbye to a lot of people, he consciously decided to stop taking any medication,” adds director James Rogan. “At that time the medication was very complicated because it had a lot of side effects. It wasn’t what it is now. His eyes were failing. He knew that there was only one way that it was going to end. He had wanted to beat it but at that time there was still no real prospect of a cure. That was the tragedy of it.”

Interviewing Mercury’s sister, close friends and bandmates to trace his last years, The Final Act paints a picture of a shy and private man who left his shell for dust and transformed into a 1,000mph Mr Fahrenheit the moment he stepped onstage. “If you’re shy, it’s being yourself that’s the difficult thing,” says Hall. “I imagine to stand on a stage and talk about his life to an audience may have been challenging, but to put on a mask and a coat and have a song and a framework in which you can perform – I can see that that chimed fine with the shyness because you’re performing. It’s when you’re being yourself and all of that comes off, that is the very private, very closed space.”

“He built a world for himself, a sort of a safe space,” says Rogan. “It made more sense when Brian May put Freddie in the tradition of Little Richard and said he screamed his passion. Suddenly you see that intensity of passion that was in him, that he could express with this extraordinary instrument that was his voice.”

Rogan plotted the film as a musical, with songs such as “Somebody to Love”, “I Want to Break Free”, “Who Wants to Live Forever”, “The Great Pretender” and “The Show Must Go On” documenting Mercury’s personal journey as a closeted gay man facing a terminal diagnosis, even if he didn’t pen them all himself. “As soon as he sang them,” he says, “they took on both a universal and a personal meaning at the same time.” Journalist and friend of Mercury, David Wigg, says as much in the film, quoting Mercury as telling him, “everything I am is in the songs”. Which presents the heartbreaking reality of an artist laying bare his secret unfolding tragedy, lightly coded, in song even as he was forced to live a very public lie.

There are touching moments when his façade cracks and the hurt spills out. Wigg quotes from an interview he conducted with Freddie, on the effect the AIDS pandemic had had on his lifestyle: “I’ve stopped going out,” Mercury said, “I’ve almost become a nun. I thought sex was very important to me… I lived through sex… now I’ve just gone completely the other way. It’s frightened me to death. I’ve just stopped having sex. For me sex was an integral ingredient in what I was doing. It was excess in every direction. But I don’t miss it.” When the tape clicked off, however, Mercury came clean. “He said, ‘I’m going to fight it,’” Wigg attests. “‘We’re going to find a cure.’”

For Rogan and Hall, placing Mercury’s death within the wider context of the AIDS epidemic in the Eighties and Nineties was vital. They include the stories of others affected by or lost to the disease in the dark years before advances in treatment meant that a diagnosis was no longer necessarily a death sentence, and when infection with what some vocal religious figures called “God’s revenge on homosexuals” was widely portrayed as a mark of shame or guilt.

“One of the themes in the film is that all of these people that were lost were somebody to love,” Hall explains. “Freddie was loved for his talent and he died surrounded by people who loved him, but many people didn’t. And we wanted to talk about that… Where we are with Covid at the moment, there’s a huge culture of blame going on. Who’s at fault and who deserves to get ill and who doesn’t and who should be wearing masks and who shouldn’t. There’s so much mudslinging going around and it chimed a lot with the HIV/AIDS epidemic – [there were] similar conversations about blame and shaming.”

Earlier this year, May told me about the years of denial he experienced in the wake of Mercury’s death. “We knew it was close and yet we denied it,” he said. “I think, in ourselves, we thought, no, Freddie can’t go, it can’t happen, something has to rescue Freddie, he’s Freddie after all. How could he be allowed to slip away from us? I think both Roger and I will tell you that we over-grieved for a very long time. And by over-grieving I mean we kind of denied that the past existed, almost.”

What comes across in The Final Act, however, is the anger the surviving members of Queen felt about the handling of the story in the media. “There was this talk of ‘well, y’know, he was gay, he kind of deserved it, he lived that kind of promiscuous lifestyle, it was gonna happen’,” May says. “We thought, ‘Oh my god, you people have no idea of what this disease really is and no feeling about the morality of what you’re saying.’” Taylor even admits to trying to run down one of the journalists besieging Mercury’s house.

In the following days the band appeared on TV-am to rail against the homophobia stirred up by Mercury’s death, and the film ends with their grandest statement of love and brotherhood: the 1992 Freddie Mercury Tribute Concert at Wembley Stadium, featuring a dazzling array of stars including Elton John, David Bowie, George Michael, Guns N’ Roses, Metallica and Liza Minelli, and watched by a global audience of up to one billion. Rogan quotes research suggesting that public approval of same-sex relationships, which had plummeted amid the politicised “moral panic” of the Eighties HIV epidemic, improved dramatically around the time of the concert.

“The concert effectively was where Freddie’s friends, his bandmates who had been with him for decades, wanted to stand up and say, ‘this has to change,’” he says. “I remember it being a huge, huge moment, the moment that the people around me suddenly stopped talking about AIDS with fear and talked about it more with sympathy. It changed the conversation.”

It’s arguable, then, that Freddie Mercury made as great a cultural impact in death as in life. A true lost champion.

‘Freddie Mercury: The Final Act’ is on BBC Two on 27 November and is also available on BBC iPlayer