ONCE he was seen as a saviour. Now he is being portrayed as a sex maniac. The debunking of the Mao Zedong myth will reach perhaps its most controversial phase tomorrow, with the airing of a BBC television documentary which alleges the Great Helmsman liked to choose scores of young girls for his bed. The story itself is hardly new. As any reader of Mao biographies will know, the suggestion that he had an eye for the ladies, even in his dying days, has been around for many years. But from the point of view of Beijing - and perhaps also the Foreign Office - the timing of the BBC programme could hardly have been worse, coming as it does in the run-up to the 100th anniversary of Mao's birth. The most salacious details, have already been extensively trailed in the British press over the past few weeks, allowing plenty of time for the barometer at the Chinese Embassy in London to rise. Given the icy state of Sino-British relations it is not surprising Beijing sees this as part of a British conspiracy. That explains, even if it does not justify, China's demand that the British Government prevent the programme from being broadcast. It would be unforgivable if China chose to retaliate against BBC journalists perhaps by closing the Beijing bureau. However journalists would only be made the scapegoats for deteriorating relations between Britain and China. As BBC World Service Managing Director Robert Phyllis told the House of Commons Foreign Affairs Select Committee last week, programmes are being jammed more heavily than even after the events of June 1989, while the BBC is limited to two correspondents in Beijing - fewer than those from the US, Japan, Australia and France. Britain has said that it cannot comply with China's demand to take the programme off the air. Unlike the state-controlled media in China, the BBC is largely independent and cannot be told what to do by the government. The Hong Kong media operates along the same principles of being free from government interference. China's handling of the incident can only reinforce concerns about press freedom in the territory after 1997. By over-reacting to the BBC documentary, China is lending credence to the allegations contained in the programme and ensures that the controversy overshadows the true significance of the Great Helmsman's centenary.