(15, 114 mins) Philip Seymour Hoffman, Catherine Keener, Clifton Collins Jr, Mark Pellegrino, Bruce Greenwood, Amy Ryan, Bob Balaban. Directed by Bennett Miller

Philip Seymour Hoffman delivers a mesmerising, BAFTA award-winning performance as Truman Capote in Bennett Miller's critically-feted feature.

The versatile actor, so often relegated to colourful supporting roles, assumes his leading part with gusto, disappearing entirely beneath the skin of his waspish alter ego.

It's a breathtaking metamorphosis: Hoffman effortlessly captures the fey mannerisms and high-pitched voice of Capote, gradually revealing the vanity and insecurities which were ultimately to become his downfall.

The film focuses on the years of Capote's life when he became interested, and later obsessed, with drifters Perry Smith (Collins Jr) and Richard Hickock (Pellegrino), the two men arrested and charged with the murders of an entire Kansas family in November 1959.

As Capote pursues the suspects with a view to writing an article for The New Yorker, he strikes up a strangely intense relationship with Smith, seriously compromising his objectivity.

He secures the trust of both men by securing them new legal counsel, giving Smith and Hickock hope of an appeal.

What begins as a magazine article soon becomes the basis of a groundbreaking book - In Cold Blood - the non-fiction novel that would become the publishing phenomenon of Sixties America.

Capote is all too aware of the literary goldmine before him: "Sometimes, when I think how good it could be, I can hardly breathe," he gasps.

Ambition gradually consumes the writer, and he follows the trial of Smith and Hickock to its devastating conclusion, wrecking relationships with long-term lover Jack Dunphy (Greenwood) and childhood friend Nelle Harper Lee (Keener).

Screenwriter Dan Futterman evokes a richly detailed portrait of a tortured genius, following his subject from the heights of celebrity to the pits of despair.

In Cold Blood was the last book Capote ever finished. Emboldened by Hoffman's tour-de-force portrayal, Capote comes across as a brilliant yet tragically flawed creature: Sparkling and witty, yet scarred by a boundless capacity for deception and self-deception.

"I did everything I could, I truly did," Truman sobs to the two prisoners as they stand on death row. When he repeats this assertion ("There isn't anything I could have done to save them") to Harper, she retorts, "Maybe not, but the fact is, you didn't want to."

Indeed. What better way to end the book than the deaths of the two protagonists?

Supporting performances are superlative, including Keener's memorable turn as Lee, whose brush with literary success with To Kill A Mockingbird causes Capote to sneer, "To be honest, I don't see what all the fuss is about." Collins Jr is also impressive as the naively trusting prisoner.

Smith and Hickock never stood a chance. They were lambs to the slaughter, sacrificed at the altar of Capote's ruthless pursuit of adulation.