“This is the story . . . of a ship,” intones a reedy narrator (Leslie Howard) at the beginning of this classic wartime tribute to the British Navy. It's all aboard the destroyer Torrin as she sets off to fight the evil Hun stocked with sugar, gas masks, and rum, and with a motley assortment of properly British souls on deck, from the courageous captain (Noel Coward) to Ordinary Seaman Shorty Blake (John Mills) to the cowardly gunner (Richard Attenborough, in his film debut). Fighting in Dunkirk or adrift off Crete, craving their “cuppa” between battles, the men continually flash back to what they're fighting for: a wife and two kids on the country estate, a mother-in-law in the spare bedroom, Churchill on the radio-in other words, England. More than a tidy vessel of homefront propaganda, this Lean/Coward collaboration showcases how a country imagines itself during war.