No one knows for sure why London’s Metropolitan Police are called the Old Bill. The police website at www.metpolice.co.uk gives thirteen possible origins, ranging from King William IV’s nickname ‘Old Bill’ who happened to be the reigning monarch when the police were formed by Robert Peel in 1829, to a popular Sergeant Bill Smith in the 1860s. Others maintain it is simply rhyming slang – ‘bill and coo’ for ‘the boys in blue’ but this seems unlikely. Eric Partridge, on the other hand, says its first use is in fact much later, from the 1950s. Some sources maintain it comes from the British TV Series ‘The Bill’ but when this TV series first went on air in 1984, ‘Old Bill’ was already established as a nickname and the TV series merely popularised it. ‘Old Bill’ sometimes refers to an army veteran rather than the police and the source for this is Bruce Bairnsfather the World War I cartoonist. His famous WWI cartoon shows two British soldiers, up to their knees in water, sheltering in a shell hole. One of the soldiers, Bill, says to the other, “If you know of a better ‘ole, go to it.” The cartoon became world famous and ‘Old Bill’ soon passed into the language as an expression for a veteran soldier. Just as quickly, however, it also died out and is rarely heard in this context these days. Meanwhile, the debate about the police origin for ‘Old Bill’ continues and is still unresolved.