In November, during his and Evans' return flight from Kenya, McCartney had an idea for a song that eventually formed the impetus of the "Sgt. Pepper" concept. His idea involved an Edwardian-era military band, for which Evans invented a name in the style of contemporary San Francisco-based groups such as Big Brother and the Holding Company and Quicksilver Messenger Service. In February 1967, McCartney suggested that the new album should represent a performance by the fictional band. This alter ego group would give them the freedom to experiment musically by releasing them from their image as Beatles. Martin recalled that the concept was not discussed at the start of the sessions, but it subsequently gave the album "a life of its own".