Since the miners' strike seven years ago, productivity in Britain's mines has soared and efficiency improved beyond all expectations. But these gains have been accompanied by dozens of pit closures and thousands of redundancies as the coal industry has felt the chill blast of market forces. Now the Conservatives are pledged to privatise the remainder of British Coal if they win the General Election. Jane Corbin reports from the coalfields of Yorkshire, Nottinghamshire and South Wales on the bitter mood of betrayal in the pits.