The manager of the Locarno Dance Hall at Streatham went to see 'Me and My Girl' and decided that 'The Lambeth Walk' might be turned into a ballroom diversion. Miss England, the chief of his dancing staff, then evolved the knee-slapping, the stamps, the turns and the shout of "Oi". Success was instantaneous at the Locarno and subsequently in the main dance-halls of England and of Scotland (where "Hoch oi" is shouted instead of "Oi").
Source Guardian https://www.theguardian.com/theguardian/2014/jul/26/archive-1938-lambeth-walk-dance
Image Streatham's Kate Carney, London's coster queen of the music halls, practising the Lambeth Walk with her daughter Dolly, 5 October 1938. Photograph: JA Hampton/Getty Images