In 1961 John Lewis Oxford Street commissioned the Yorkshire-born artist to create a work that evoked common interest and ownership. Placed 13 feet above the busy cross-section between Holles Street and Oxford Street, it is estimated that the sculpture is seen by 200 million people a year.
For further information on hidden public statues and artworks there is an article by the BBC : From Gormley to Rodin: The famous artworks hidden in plain sight here