"Knees Up Mother Brown" is a song, published in 1938, by when it had already been known for some years. It dates to at least 1918 and appears to have been sung widely in London on 11 November of that year, Armistice Night, at the end of the First World War.[1] The 1938 version was attributed to Bert Lee, Harris Weston and I Taylor.[2]
The song became popular in English public houses and was particularly associated with Cockney culture. During the Second World War it was performed frequently by Elsie and Doris Waters. The expression "knees up" came to mean a party or a dance. The tune has been adopted by football fans for various chants, most recognisably with the words "Who Ate All the Pies?". It was also the inspiration for the song "Step in Time" written by the Sherman Brothers for the Walt Disney film Mary Poppins. According to Richard Sherman, the dance was taught to Walt Disney, Tony Walton, and others and the Sherman Brothers witnessed them doing the dance and got the idea for "Step in Time".[3]