What is the old bill?

The Old Bill is a slang term used to refer to police officers, especially those of the British police force. This term probably originated from the use of the word "billet" in the 19th century, which was used to refer to a place where soldiers were stationed. The term "Old Bill" became popular after it was used in a comic strip that appeared in the Daily Mirror newspaper in Britain in the early 1900s. The comic strip featured a detective called "Old Bill" who was known for his humorous and bumbling ways. The character became so popular that it spawned a series of books and even a play. Today, the term "Old Bill" is still used occasionally referring to police officers in a humorous or affectionate way.