Like its predecessor, You're a Sap, Mr. Jap, Spinach Fer Britain is a World War II-themed short and was likewise kept out of distribution for several decades due to its propagandistic nature and prevalent portrayals of Nazism, until it received an official release on November 2003 in a DVD collection of Popeye cartoons produced between 1941 and 1943. It also had limited airings on Cartoon Network as part of The Popeye Show.
The short opens with five Nazi soldiers patrolling the coast Europe in a U-boat, destroying everything they encounter. Each time they defeat an enemy, one of them jumps onto the bow of the U-boat and the Nazi captain emerges as they shout "HEIL HITLER" while exchanging salutes.
Meanwhile, Popeye the Sailor is heading for Britain with a shipment of spinach to donate as a war ration; his ship is attacked and sunk by the Nazi patrol before he can reach Britain. Popeye manages to escape with his spinach in a rowboat but is pursued by the Nazis. Popeye flips the U-boat upside-down and quickly withdraws.
However, Popeye rows into a minefield and his boat is destroyed before he can escape. Popeye quickly collects all his spinach before the U-boat catches up with him. The Nazis ready their U-boat's turret but smoke from Popeye's pipe causes it to sneeze and fire uncontrollably, knocking Popeye out cold and sending his spinach flying into the air. The Nazis, believing Popeye to be dead, emerge from their U-boat and salute; all of Popeye's spinach falls through the U-boat's bulkhead door. Popeye, dazed and unconscious, topples down to the ocean floor, taking the U-boat's propeller with him. Popeye quickly regains consciousness and takes out a can of spinach; swallowing its contents causes his arm to grow a depth charge. Using the propeller for transportation, he blows a hole in the Nazis U-boat. One-by-one, four Nazi soldiers emerge from the ruined sub as Popeye delivers them each a single uppercut, causing them to fly up into the minefield to their deaths.
Popeye rows the half-destroyed U-boat to 10 Downing Street in London; he goes into fogginess and the half-destroyed U-boat ends up crashing into traffic, he is greeted with many cheers upon his arrival. Popeye exits the sub along with the Nazi captain, shouting "HEIL HITLER" and saluting once he exits. Popeye stuffs him back into the U-boat and puffs his tobacco pipe to "V for Victory" before the short irises out.
- Spinach Fer Britain at the Internet Movie Database