“The Man Who Broke the Bank at Monte Carlo” is a British music song that was made popular by Charles Coburn. I know it’s in at least two films: Lawrence of Arabia (which I was watching on TV today) and The Magnificent Ambersons.
I have attached clips from both. In the Amberson clip, it is sung near the end. It is also at the end of the much briefer Lawrence clip.
Sad! 