Billy Elliot's story, one of a miner's son nursing a secret dream to be a ballet dancer, is based in a northern community whose living in the mining industry was being threatened by Margaret Thatcher's government in the early 1980s, and the song that opens Act Two - 'Merry Christmas Maggie Thatcher' - contains a key lyric, 'We all celebrate the day cos it's on day closer to your death."
Stephen Daldry tells HuffPostUK he was undecided whether to include the song or not.
"There was a debate whether we should leave it or cut it out," he remembers. "And most people felt that we shouldn’t sing it out of respect. What was hard to gauge in those early days after she died was the mixed response to Mrs Thatcher’s legacy. I felt that the country in the end would feel quite split on how they felt about her. Even though they were going to give her a state funeral, that wasn’t necessarily going to be the most popular choice.
"And so we put it to a vote in the audience. We told them what the song was about, whether they felt it was appropriate or not and whether they wanted to it. I think only four people voted for it not to be sung out of 1,400."
As 'Billy Elliot The Musical' becomes available for viewers to enjoy at home, we asked Stephen - the director of the original film in 2000, as well as the musical version that's done so well around the world - what is the enduring magic behind the tale?
"What we found amazing when we did the film was how much the story resonated in different cultures around the world despite the fact that it is so rooted in the very specific and authentic experience of the north-east of England," muses Stephen, who's also had massive screen hits with 'The Hours', 'The Reader' and the recent 'Trash'.
"The theme of a community under threat, a community trying to hold itself together, a family falling apart but trying to hold itself together, and a young person trying to find their own voice – all these themes seems to resonate in radically different cultures around the world.
Far from being snobbish about seeing his screen jewel come to the stage, Stephen is convinced the story has found its natural home.
"I think that we feel in the show the story has found its natural habitat and that habitat is a theatrical habitat. It’s particularly successful onstage. We hoped to not just replicate the success of the film in the show, and I think the show is now the right medium in which the story is being told.
"We all loved making the film but the show is much more acute, so much more powerful. I would hope that it translates to different cultures in a way that is even more successful than the film."
What's different about the live show, of course, is the huge pressure on the young performer to pull off every move, every spin, time and time again, without the benefit of any nifty camera edits to rescue him, something of which Stephen is all too aware...
"We built the show to the point at which it was almost unperformable," he admits.
"The challenges and the demands made on the young chap paying Billy Elliot are so extreme that there is a tension in the show which is, can the show actually be physically done? I think the audience is very aware of the extreme challenges placed upon that young performer. And that’s part of what makes it so exciting in real time. There’s no cheats.
"I’ve likened it to playing Hamlet and running a marathon at the same time. There is no other part like it that has ever been created for a young performer in any show in the history of show business."
'Billy Elliot The Musical Live' is out on Blu-ray and DVD now, from Universal Pictures (UK)