Following Christopher Nolan’s epic “Dunkirk,” Joe Wright’s “Darkest Hour” further illuminates that massive evacuation in 1940, utilizing a dazzling performance by Gary Oldman as that plummy wordsmith, Winston Churchill. Actually, the films are complementary.

Within days of becoming Prime Minister of Great Britain, Winston Churchill was faced with the choice of negotiating a peace treaty with Adolf Hitler, whom he considers a madman, or standing firm, engaging his nation in World War II to fight for freedom from tyranny.

As Nazi Germany’s troops rolled across Western Europe, invading France, encircling and pushing 400,000 Allied troops into the sea at Dunkirk, Churchill found himself coping not only with his own cabinet and the pacifist Parliament plotting against him but also skeptical King George VI (Ben Mendelsohn).

When the King asks, “How do you manage drinking during the day?” Churchill curtly replies, “Practice.”

Supported by his devoted wife, Clementine (Kristin Scott Thomas), yet wracked by depression and self-doubt over the defeat at Gallipoli, Churchill duly considers appeasement but, ultimately, defies former Prime Minister Neville Chamberlain (Ronald Pickup) and Foreign Secretary Lord Halifax (Stephen Dillane) and does what he thinks is right.

“How many more dictators must be appeased before we learn? You cannot reason with a tiger when your head is in its mouth!”

Scripted by Anthony McCarten (“The Theory of Everything”), it’s inventively directed by Joe Wright (“Pride & Prejudice,” “Anna Karenina”), who previously staged the Dunkirk scenes in “Atonement” (2007).

Admittedly, the simplistic yet superbly structured scene of Churchill going out to “meet the working people” in London’s Underground is fictionalized. Added for dramatic purposes, it’s remarkably effective.

Although veteran actor Gary Oldman has only been nominated once, for “Tinker Tailor Soldier Spy,” he will probably walk off with the Academy Award as Best Actor. Propelled by incredible, almost manic, energy, both mental and physical - augmented by jowly makeup and padding - he transforms himself into the pugnacious 20th century icon.

On the Granger Movie Gauge of 1 to 10, “Darkest Hour” is a suitably stylish 7, emerging as a career-defining Oscar-vehicle for Gary Oldman.