In January, every US TV station – cable and network – shows off its forthcoming programmes. This year, there was a lot of deserved self-congratulation. Dustin Hoffman's Luck (HBO) is an impressive study of the murky underworld of horse racing and mob tactics; Smash (NBC) is an ambitious take on the High School Musical/Glee trope about the backstage antics of a Broadway musical about Marilyn Monroe; Kiefer Sutherland's riff as the father of a mute Aspergers sufferer sets post-9/11 American parenting in a sharp, cruel context. Everyone agrees, we're in a golden age of TV.

BBC4, meanwhile, has a show coming up that makes these epics look like amateur hour. The Singing Detective meshes the finest bits of Glee and Smash with the edgy darkness of Dexter and Breaking Bad, and features a wizened Tony Soprano-style figure at its core. It breaks every TV convention: the star, played by Michael Gambon, is a podgy middle-aged man raddled with skin disease, battling hallucinations and dark memories of childhood abuse. And yet the tempo is upbeat – even merry – and the tale is hypnotic and addictive.

Philip E Marlow lies in a hospital bed that could be in a 70s sitcom. His dreams enter 1940s noir, with mystery, song and thrills. His memories of growing up in post-industrial mining towns blur in and out of both settings. It's sort of a musical, sort of a thriller, sort of a comedy … it's the pinnacle of the golden age. The golden age of the 1980s, that is.

Dennis Potter's masterpiece is 25 years old but still feels avant garde. It's got the kind of confidence in the audience and in the medium that American writers are only just discovering. The smouldering Brit-made-good Damian Lewis – talking in Los Angeles about his Golden Globe-winning cable drama Homeland (coming to More4 this month) – said it was a shame that we don't have the writers to pen that sort of stuff in the UK. Well, we did once.

The Singing Detective's influence is hard to quantify but its not stretching things too far to say that it helped create the current Golden Age. Steve Bochco, Alan Ball and Charlie Kaufman all cite Potter as a key influence. Robert Downey Jnr starred in a flawed remake of the show in 2003 – although, let's be honest, if it's got Downey it's a gem.

I'd go toe to toe on The Singing Detective as a desert island DVD of best-ever TV. How many shows get props from the Manic Street Preachers, Franz Ferdinand and Elbow while framing the works of post-modern novelists like Paul Auster? (Auster's New York Trilogy riffed on identity and hallucination – with author and detective characters swapping roles, much as Marlow swapped with Marlow in Detective. Auster published in 1987. The Singing Detective was out on PBS a year earlier.)

Of course you could say – and probably will – "Why, oh why, can't we do it any more?/Where is the next Dennis Potter coming from?/It's all Thatcher's fault/Sod you BBC"… but that all misses the point. This is one of the best pieces of TV you'll see in your life. The Iron Lady wouldn't be as it is without it. True Blood likewise. Forget the context. Just watch this show.