Graham Chapman was actually too SOBER to walk the bridge
Most Python fans know that the late, great Graham Chapman was battling alcoholism during the time 'Holy Grail' was filmed. I had long ago heard a rumor that the scene in which King Arthur walks across the suspended bridge near the end of the film was delayed because Chapman was "too drunk" to perform the feat. Recently, however, I found a youtube video in which Chapman admits that he finally came to grips with his drinking problem during that time. Apparently, that particular scene was one of the first scenes filmed, and it occurred early in the morning. Chapman found himself hungover and shaking so much that he couldn't walk across the bridge. He asked several people on the set if they had any "juice" to spare, but being so early in the morning, nobody could indulge him. Being a friend of Bill W, this makes perfect sense! The alcoholic needs alcohol to function and will MISfunction without it. He said that he did eventually do the deed even without his "liquid courage". By 'Life of Brian', he was a sober man--God bless him!
He who conquers himself is mightier than he who conquers a city.