King Rat

"James Clavell incorporated a few of his own experiences as a British POW in his novel King Rat. Bryan Forbes' film version stars George Segal as the mastermind of all black market operations in a Japanese prison camp. He is called ""King Rat"" because of his breeding of rodents to serve as food for his emaciated fellow prisoners; the nickname also alludes to Segal's shifty personality. British officer James Fox helps Segal expand his operation to include trading with the Japanese officers. Though on surface level a thoroughly selfish sort, Segal saves the ailing Fox's life by wangling precious antibiotics from the guards."