GARY Oldman leads the charge with an electrifying central performance as Prime Minister Winston Churchill in director Joe Wright’s compelling wartime chamber piece that would make for an effective opposite-side-of-the-same-coin companion to Christopher Nolan’s Dunkirk.

It’s May 1940 and, with the war heading for outright disaster for Britain, beleaguered PM Neville Chamberlain (Ronald Pickup) realises he must step down. After much contention his Cabinet decides to give the job to the unpredictable and hot-headed Churchill, the only man whom both the opposition and the country will accept.

Encouraged by the support of his beloved wife Clementine (Kristin Scott Thomas), he takes on the mammoth task of navigating his country through what increasingly feels like an unwinnable battle. It then becomes the story of how Churchill has to fight a war on all sides as he makes decisions that will define his country’s future. This includes his supposed closest allies disagreeing with his unusual methods, ever-willing to throw his past mistakes in his face.

“You cannot reason with a tiger when your head is in its mouth!” he bellows as he storms out of a room full of men who disagree with his decision not to enter into peace talks with Hitler.

It’s in these sorts of moments where the film soars, giving Oldman the chance to shine in one of his finest ever performances and the one that is all but guaranteed to win him his long overdue Oscar.

Oldman joins other recent actors to portray arguably Britain’s most famous leader, including John Lithgow in TV’s The Crown and Brian Cox in last year’s under-appreciated drama Churchill.

But Oldman makes the role entirely his own, giving a masterfully studied performance that captures the idiosyncratic mannerisms and temperamental nature which those around him – from his unwavering wife to put-upon secretary Elizabeth Layton (Lily James) – must deal with on a day-to-day basis.

But he also transcends cheap caricature that the fat-suit and layers of make-up might suggest to bring out the humanity hidden below the bluster and the fragility buried under outward displays of defiant strength and rousing speeches. We really do get a sense of what made him both an effective leader and a loved man.

Not all of it entirely works; for example, there’s a scene where Churchill heeds the words of King George VI (Ben Mendelsohn) and goes to meet with everyday folk on the Tube that, whether it really happened or not, rings false and out of place. But for the most part, anchored by Oldman’s commanding leading performance, it works as a stately and absorbingly tense piece of British cinema.