Rupert Murdoch in 1997 wrote a personal letter to China's top leaders apologising for any "misunderstanding" caused by a speech four years earlier in which he said satellite television posed a threat to totalitarian regimes, according to a new book by a former News Corp executive.

The letter assuring Jiang Zemin, then Chinese president, and then-premier Li Peng that Mr Murdoch was "a good friend of China" highlights the lengths the News Corp chairman has gone to gain entry to the country's vast but tightly controlled media market.