In P.G. Wodehouse's Jeeves stories, Bertie Wooster was indeed once arrested for stealing a policeman's helmet on Boat Race Night - an incident mentioned in 'Very Good, Jeeves!' and other stories. This wasn't about Glossop's hat, attacking Pinker, or stealing a cow-creamer - those are separate escapades. The helmet theft is a recurring reference to Bertie's youthful misadventures.