Any Day Now is a torch song of hope and tragedy.

That “Any Day Now” has been pigeonholed as an LGBT movie does it, and its message, something of a disservice. It deserves a much wider audience than it may receive thanks to that label, and I suspect it won’t gain the traction at the UK box office it should have.

Alan Cumming plays Rudy Donatello, a musician and drag artist working in a gay nightclub in 1979 Hollywood where he meets Paul Fliger (Garret Dillahunt), a recently divorced district attorney, struggling to come out of the closet. Back at his apartment, Rudy finds his drug-addicted prostitute neighbour has left her son Marco, a 14-year-old with Down Syndrome home alone. When it becomes apparent she isn’t coming home, Rudy takes Marco in. Family Services soon intervene and take Marco into care and so Rudy enlists Paul to help him gain custody of Marco.

Alan Cumming has never been better than he is here, and he imbues Rudy with a soulful pathos, veneered with playful exuberance that slowly transforms into a tender, nurturing but fiercely protective parental love towards Marco, played with real subtlety and skill by Isaac Leyva. The supporting cast is very, very good with Frances Fisher, Alan Rachins, Chris Mulkey and Gregg Henry all bring depth and authenticity to their (sometimes despicable) characters but the film belongs to Cumming. How this performance was overlooked for an Oscar nomination mystifies me.

It’s clear that in Marco, Rudy sees a chance to right some of the wrongs of his own childhood and experiences of prejudice. Because of the time constraints of the movie, Rudy and Paul’s journey from first meeting to committed relationship is necessarily truncated in favour of exploring the developing bond between the pair and Marco. For a short, sweet time we are given the privilege of seeing all three members of this unconventional and clandestine family grow and blossom before their secret is discovered and the authorities get involved. Unwilling to abandon Marco to the indifference of the state, Rudy and Marco are forced to turn to the courts to try and keep their family together.

To the credit of writer/ director Travis Fine, the film never once makes an issue out of its two potentially controversial subjects: neither homosexuality or Down Syndrome is portrayed in a glib, exploitative or sensationalist manner. In fact, one of the best features of this movie is how matter-of-factly those subjects are dealt with. No tabloid prurience here, just an authentic honesty which exposes the ugliness and devastating callousness of institutional prejudice and discrimination.

“Any Day Now” is an important and eloquent movie – and it frustrates me that it hasn’t had the attention or success that something like “The Help” did. It will manage to delight and alarm you, draw you in and then break all but the stoniest of hearts. It’s absolutely one you should allow yourself some time for quiet reflection afterwards. This is not a niche LGBT film, this is a gripping, heartfelt drama about human beings and the wonderful and awful things we do to each other.