Sometimes the 'poor man's pudding' can be the most comforting and that is certainly true of bread and butter pudding. Different forms have been around for centuries and made to use up stale bread. Maybe it should have been called bread and bone pudding though, as the earliest bread pudding was called 'whitepot' and used bone marrow instead of butter.
Today, bread and butter pudding is made as a treat whether or not the bread needs using up, and you can jazz a traditional recipe up in all sorts of ways. In this case, using marmalade.