Barry Jones, a member of Parliament and former whizz-kid on the TV quiz-show, "Pick a Box". Surely a trivia question right up his alley.
Dear Mr Kennedy,
I don't recall the film.
From your description, the use of the lily appears to be a visual pun - 'lily livered'. i.e. a coward.
Yours sincerely, Barry Jones.
Bzzzzt! Next contestant please.