Sitting on the desk of the chief executive of The Belfast Telegraph in a grand walnut-lined office was a simple glass prism.  Inside was a single sheet document about the size of a small envelope. It bore the logo of a big multinational accountancy firm, a date – March 2000 – and carried the message: “We are pleased to mark the acquisition of The Belfast Telegraph by Independent News and Media for the sum of £300 million”. It was the final brick in the wall, the last great purchase by a dynamic media empire that spanned the globe.  It was…