CHINA yesterday accused the British side of ''playing little tricks'' and undermining the fourth round of talks on Hongkong's political development. It is understood the Chinese side was opposed to the adoption of the Boundary and Election Commission Bill by the Legislative Council on Wednesday. Chinese sources said Beijing considered it vital for Britain to show sufficient sincerity when the talks were going towards concrete issues of the electoral arrangements in 1994/95. ''The Boundary and Election Commission Bill is a part of the legislation for the 1994/95 electoral arrangements,'' sources said. ''The British side has played little tricks to push through the bill at Legco just before the fourth round of talks. It is playing the time pressure tactics. ''The Chinese side is disappointed that although we have taken various initiatives to create a favourable atmosphere for the talks, the British side still shows a lack of sincerity in co-operating with us,'' sources said. Chinese and British negotiators held a three-hour session in Villa No 10 of the Diaoyutai Guesthouse yesterday. Speaking after the morning session, Sir Robin McLaren, British negotiating team leader and Ambassador to China, refused to describe the atmosphere of the talks. During the third round last week, he described the atmosphere as ''good''. Sir Robin said only that the two sides had discussed a range of topics, but refused to disclose any further details. He said he was looking forward to continuing discussions at a fifth round. Both Mr Jiang Enzhu, China's chief negotiator and Vice-Foreign Minister, and Sir Robin appeared restrained yesterday morning. Mr Jiang refused to make any comment on the fourth round of talks, saying that China's position was consistent and clear. ''I don't think I have anything to add except to say there has been rather a short gap between the last round and this round,'' Sir Robin said. Mr Jiang said: ''Progress in the talks requires both sides to show sincerity and to work hard together.'' Sir Robin said the adoption of the Boundary and Election Commission Bill should not adversely affect the talks.