HONG Kong this week has to negotiate one of the most hazardous phases in the stormy relationship between Britain and China. Mr Patten plans to table in the Legislative Council his mini-reform bill, an event which China has warned will mean the end of the talks over the territory's future political arrangements. China raised the risk factor over the weekend by reviving Deng Xiaoping's threat of an early takeover in the event of turmoil. In China's view, the Governor's decision to push ahead with electoral reforms constitutes the kind of man-made chaos which might justify its intervention. This is pure intimidation. There is no turmoil in Hong Kong. There is a crisis in Sino-British relations and as it comes to a head on Wednesday the level of nervousness in the territory can be expected to rise. But the relationship has reached crisis point before without triggering the patriarch's threat. And Hong Kong has its own dynamism, which enables it to absorb the shocks of political confrontation or to rebound quickly when it cannot absorb them. Witness the remarkable performance of the stock market, despite the tensions between the outgoing and incoming sovereign powers. Witness, too, the territory's growth in prosperity, and the way its financial and industrial integration with China continues without interruption. If China's leaders genuinely harbour fears about turmoil in the territory they can put their minds at rest, as Mr Patten said yesterday in his calm reply to the takeover warning. But they should also give their threats a rest. They should remember that the factor most likely to promote uncertainty - and therefore threaten to produce the kind of strife to which Foreign Minister Qian Qichen referred at the weekend - is bullying megaphone diplomacy. Mr Qian's warning may be counter-productive. It is too much to expect members of the Preliminary Working Committee to buck China's line on Hong Kong. But it is extraordinary that the committee should issue a communique at this volatile time endorsing Mr Deng's threat. The committee is meant to be helping to prepare the way for a smooth transition to Chinese rule in 1997, not increasing anxiety about the future course of events. It might also be expected to give China advice on how to ensure a smooth changeover. It was not doing much advising at the weekend. Nor was Premier Li Peng being helpful when he linked political and economic factors by warning that Britain's ''unfriendly and unco-operative attitude'' over the talks made it impossible to rule out deterioration in relations in other fields. Some of the''other fields'' - like the new airport project and container terminal development - are vital to Hong Kong's future growth, to the prosperity and stability Beijing has pledged to preserve. Mr Li's statement runs counter to the argument President Jiang Zemin pushed in his talks with President Bill Clinton on ties between China and the United States. It runs counter, too, to previous Chinese Government assurances on the territory's development. China has moved from reassuring the people of Hong Kong to threatening them as it threatens Mr Patten. It is in China's tactical interest to see a certain amount of trouble and uncertainty in the territory early this week, to put pressure on Mr Patten to scrap his plan to table the reform bill. But Mr Patten's course of action has a sense of inevitabilityabout it, given his very public commitment to democratic reform and the community support for his proposals concerning the ''simple issues'' on the negotiating table. The reforms are not contentious: the only controversial matter is ordering the single-seat, single-vote system for the 1995 Legco elections. Yet China opposes them vehemently. China and Britain are not far apart so much on the technicalities of the voting age, the voting system and appointments to local councils; they are divided by their attitudes to one another. As they enter this critical week, however, China and Britain should remember one fundamental point: it is a third party - the third leg of the stool - that will suffer if they cannot conduct themselves in a civilised manner. Is it really too much to expect that they might think of Hong Kong's interests before switching on the megaphones?