CHINA has warned Britain that it will insist on having the right to decide which members of the 1995 legislature qualify to remain on the first legislature of the Special Administrative Region (SAR). The warning came from a Chinese official in what was seen as a statement of Beijing's negotiating position ahead of next week's talks between Britain and China over Hongkong's political reforms. The official, who spoke on condition of anonymity, said China would not accept Britain's demand that Legislative Councillors elected in 1995 would automatically become members of the first post-1997 legislature. This would allow China to exclude those who it considered subversive, such as liberal legislators Mr Martin Lee Chu-ming and Mr Szeto Wah. ''There is no room for any wishful thinking. They should keep their eyes open and look at what is laid down in the Basic Law,'' the official said. ''The Basic Law has clearly stipulated that there are certain political requirements for the members [in the Legco elected in 1995] if they want to serve beyond 1997. We have to respect the facts.'' Beijing's condition will put it on a collision course with Britain, which is expected to reject it as it would amount to derailing the through train concept. If China insists on throwing people off the through train after reaching agreement with Britain on 1994/95 electoral arrangements, there would be no point in holding talks, said a source close to the British side. The British maintain that if China reached agreement on the 1994/95 electoral arrangements, it would only be reasonable to expect those elected under that formula to serve after 1997. An opinion poll has shown there is majority support in Hongkong for Britain's position. A total of 60 per cent of the public feel a through train arrangement for Legco is important. The poll was conducted by the Social Sciences Research Centre of the University of Hongkong (HKU) on Wednesday night. Under the Basic Law, members of the 1995 Legco who pledge allegiance to the SAR Government and meet the requirements set out in the mini-constitution may, ''upon confirmation by the Preparatory Committee'', become members of the first legislature. The SAR Preparatory Committee should be composed of mainland members and of Hongkong members, who shall constitute not less than 50 per cent of its membership, according to the Basic Law. Such arrangements have been described as the ''through train'' model aimed at maintaining continuity in the change of sovereignty. Even if Chinese and British negotiators are able to agree on the electoral methods for the 1994/95 polls next week, the Chinese official argued, it did not mean that those so elected would be given an automatic seat in the first SAR legislature. ''China does not have the right to endorse the right of the members to sit on the 1997 legislature. It is a matter with the Preparatory Committee. It is impossible to have talks about it now. This is unreasonable.'' With a clash over the through train in the offing, the official warned not to be overly optimistic on the outcome of the talks. Another Chinese source said: ''The British side is trying to exchange the Patten package for Beijing's undertaking to allow a handful of anti-China politicians to get on the through train. But China cannot barter away its principles.'' The HKU poll showed that of 541 respondents, 60 per cent said the through train was important, while 12.6 per cent felt it was not important and 20 per cent had no opinion. About 40 per cent believed the Government should not introduce the reform proposals into Legco during the negotiations. Only about 29 per cent thought otherwise , while another 12 per cent said it should be dependent on the situation. About 18 per cent declined to express an opinion on the question. At the weekly press briefing in Beijing yesterday, a Foreign Ministry spokesman remained cautious on the outcome of the forthcoming talks. Mr Wu Jianmin said: ''It is the hope of the Chinese side that, on the basis of the three accords, the upcoming talks will yield positive results.'' ''Compliance with the three accords is the basis of Sino-British cooperation on Hongkong. We are prepared to develop our co-operation with Britain on this basis so as to ensure Hongkong's smooth transition.'' The three accords are the Joint Declaration, the Basic Law and other agreements reached between China and Britain.