These were made by video technicians and were generally used to amuse colleagues and friends at the BBC Xmas parties, hence the name "Christmas Tapes". In relation to British television, Christmas tapes are unendorsed videotapes compiled by technical staff for their personal amusement and peers' enjoyment. The name originates from the 1950s, when the material was filmed at the staff's Christmas parties where impromptu sketches were carried out. As time progressed, other types of material (such as outtakes and deliberate misbehaviour) were included on the videos. Some of the most notable examples of the Christmas tape genre were made in the late 1970s and early 1980s, before the digital television era, when VT engineers started recording errors and out-takes to disk - for some viewers who saw these, it was surprising to hear television stars making mistakes and swearing onscreen.