The Government has now outlined the ground rules for cable television in Britain and given the go-ahead for applications to set up some 12 pilot projects pending a full-scale expansion of the system. In the USA. cablevislon has bieen well established for a number of years. More than a third of the people there watch television by cable with, in some areas, up to 50 channels to choose from. David Wheeler reports on the American experience and considers how cablevision is likely to develop in this country. Producer TOM READ