This whole meme about Belgium quoted in movies may have started with this one…

BRADDON: “Well now, the result of last week’s competition when we asked you to find a derogatory term for the Belgians. Well, the response was enormous and we took quite a long time sorting out the winners. There were some very clever entries. Mrs. Hatred of Leicester Said “let’s not call them anything, let’s just ignore them” … and a Mr. St John of Hurtfingdou said he couldn’t think of anything more derogatory than Belgians. But in the end we settled on three choices: number three … “the Sprouts”, sent in by Mrs. Vicious of Hastings, very nice ; number two “the Phlegms” from Mrs. Childmolester of Worthing; but the winner was undoubtedly from Mrs. No-Supper-For-You from Norwood in Lancashire “Miserable Fat Belgian Bastards”. Very good – thank you, Carol. “