A MAINLAND representative on the Joint Liaison Group's (JLG) airport committee, Mr Chen Keqiang, yesterday demanded that Britain raise the question of operating rights of the proposed Container Terminal Nine (CT9) at the next JLG meeting. Mr Chen, who is also Economic Affairs Department director at the Hongkong branch of the New China News Agency, urged the Hongkong Government to submit detailed documents concerning the operation of CT9 to Chinese representatives as soon as possible. ''The operation rights of both CT9 and the proposed Container Terminal 10 will straddle 1997 and thus involve the sovereignty of China,'' he said. ''It is necessary for the Hongkong Government to seek the approval of China before any decision is made on the operation rights of the two terminals.'' But the British Foreign Ministry's Hongkong spokesman, Mr Chris Osborne, said they had no intention of raising the issue of CT9 at the JLG meeting. ''There is no need to discuss the question of CT9 at the JLG meeting because it does not involve the question of a franchise at all,'' Mr Osborne said.