Gary Oldman turns Darkest Hour into one of his finest ones.

A British icon. A pivotal moment in history. A desperate race against time. “Darkest Hour” sheds some light on the earliest days of Winston Churchill’s premiership as Europe faced annihilation by the Nazi horde and the British political establishment teetered on the brink of self-destruction.

This is no dry history lesson, though, thanks to a superlative and transformational performance from Gary Oldman. His Churchill is every bit the avuncular, truculent British Bulldog of legend, humanised by his own doubts and fears even as he fends off the doubts and doubters that besiege and surround him.

Joe Wright’s beautifully photographed wartime biography is immeasurably strengthened by the “House Of Cards” (the good, British original one) plotting and scheming which ripples through parliament and the war cabinet. The conspiratorial backstabbing and conspiring add a horrifying frisson of political power plays to an already desperate international crisis and looming military catastrophe.

“Darkest Hour” is Winston Churchill as the archetypal British ‘superhero’. While it tacitly acknowledges some of his previous misadventures, both personal and professional, it doesn’t dwell on some of his more questionable or problematic decisions and actions, nor should it have to. There’s no imperative when portraying Hitler, for example, to ensure a balanced appraisal that includes his vegetarianism or his artistic ambitions. There seems to be, in the current climate of wilfully untruthful and dissembling political and public discourse, a need to not only acknowledge but reappraise and redefine previously sacrosanct figures by their worst actions and failings, to protect ourselves from the failings of fallen heroes by making sure their every action has been weighed in the balance and there are no more surprises in store. Nobody can deny there was almost as much red in the ledger of Churchill’s life as there was black but that doesn’t diminish his achievement in the weeks covered by this film. This film is a tale of ‘cometh the hour, cometh the man’. For all his flaws and failings, Churchill was the man the country and government needed at that time, the man who could and would make the decisions and difficult choices that others were unwilling or incapable of making.

As a tense political wartime drama, it’s cracking entertainment. As a biography, it’s a sensationally insightful performance. And as the first part of a loose historic trilogy which continues in “Dunkirk” and concludes in “Churchill“, it’s one of Winston’s finest (two) hours.