You might find this interesting: I've been re-reading a series of books published by Time/Life, on the history of WW2. Within the book titled "The Battle of Britain," I came across the term "buskers." The reference was used in the description of rigors of the Londoners as they sought safety in the underground subways during the bombings. I quote: "Many of the stations' residents arranged their own amusments. Often a community sing would be going on. And there were always plenty of BUSKERS around - the entertainers who in peacetime performed on the street for people standing in queus at theaters and cinemas. They performed in just as lively a fashion for their new audiences in the underground. At Aldwych, in the center of the theater district, such famous stars as Laurence Olivier, Vivien Leigh and Ivor Novello would come down after their evening performances and present impromptu songs and sketches."   

I hope this adds to the discussion. Bob