"How long we got left?" winces a not-well-looking Hank Williams (Tom Hiddleston) from the sofa of a dimly lit Nashville recording studio in a scene towards the end of I Saw the Light.Viewers keeping score will know it's not long at all. Marc Abraham's biopic has slunk so formulaically through the Hank Williams life story there are only two major events to be chalked off: the recording of Your Cheatin' Heart, and the fateful road trip during which Williams's own heart gave out, under a fog of morphine, at the slender age of 29.In the studio, Hiddleston reaches for his guitar and croaks his way through the first verse of Your Cheatin' Heart. The moment's wrung out for maximum poignancy: hollow vocals ringing in the sepulchral gloom. But you can't help but think the unveiling of a song that shook up popular music should have felt less inevitable.I Saw the Light isn't big on surprises. From dark-period montages to split-second reversals of fate in the recording booth, the genre's most egregious clichés aren't just put to work, but paraded like prize sheep.The film follows Williams from his 1944 marriage to his first wife Audrey (Elizabeth Olsen), herself an ambitious but not especially talented singer, to his death on New Year's Day of 1953. Hiddleston is an intriguingly counter-intuitive choice for the title role of the Alabaman singer-songwriter, and though he bites down hard, his teeth never sink in - perhaps because the script never gives them much to sink into.Beneath his satiny charisma and eager smile, Hiddleston's secret weapon is a barely perceptible ripple of unspoken cruelty. It's what ties together his work in films as diverse as High-Rise, Only Lovers Left Alive and Avengers Assemble.But, as Williams, he mostly has to be equal parts earnest and tragic, which doesn't suit him. There is, however, one standout moment on the stage of the Grand Ole Opry, as Williams becomes gradually aware of his power over the audience while performing Lovesick Blues against the concert promoter's advice.As Audrey, Olsen doesn't fare better. The actress's trademark mercurial intensity is replaced by what feels like a shrill Reese Witherspoon impersonation. Again, you sense that's all she had to work with. Rather than attempting to explore the mechanisms of Williams's musical genius, Abraham's screenplay focuses instead on his boozing and philandering, and the music itself becomes an incidental detail in a flimsy perils-of-fame soap opera. It's one thing to show us Williams on stage, looking the part, silhouetted in Ovaltine light. But if the film doesn't help us understand why he's there - well, why bother watching when you can listen? - ©The Daily Telegraph..