Peter II assumed the role on an unofficial basis from his predecessor , Peter .
Peter II was a black cat who was employed as Chief Mouser to the Cabinet Office in 1946 and 1947 , during the government of Clement Attlee .
Chief Mouser   assumed the role on an unofficial basis from Peter II 's predecessor Chief Mouser Peter .
Peter II was a black cat who was employed as Chief Mouser to the Cabinet Office in 1946 and 1947 , during the government of Clement Attlee .