COUNCILLORS last night backed a motion calling for the controversial Complaints Against the Police Office (CAPO) to be replaced by an independent panel. United Democrat Mr James To Kun-sun's motion survived the challenge of appointed legislator Mrs Peggy Lam Pei Yu-dja's amendment by a meagre five-vote margin (29 to 24) after a 21/2-hour debate. Mrs Lam's amendment, which suggested a watered-down option of allowing civilians to join CAPO, was backed by the Government. Secretary for Security Mr Alistair Asprey refused to say whether the Government would abide by Mr To's motion. ''The only thing I've got to say is that I have made views of the administration, I hope, very clearly, in my speech and at this stage I have nothing to add to that,'' Mr Asprey said. He said during the debate that making CAPO independent would not be ''necessary or desirable''. But legislators cited the extremely low proven rate of complaints as ample evidence for an independent CAPO to inspire public confidence. ''In 1992, there were 1,111 cases either non-pursuable or withdrawn, and 195 cases which lacked sufficient evidence, that added up to a total of 98.9 per cent of the total cases,'' Mr To said. His party colleague Mr Man Sai-cheong, who is vice-chairman of the Police Complaints Committee - which monitors CAPO - said there had been cases where CAPO officers protected colleagues in the force against complaints. Veteran legislator Mrs Elsie Tu, long-time advocate of an independent CAPO, said the low substantiation rate of complaints against the police had placed a question mark against the impartiality of the complaints body. ''It is totally unacceptable that police should judge police, especially when the only likely witnesses are also police,'' she said. The legal profession's representative in Legco, Mr Simon Ip Sik-on, said the issue was ''an abuse of state power'' which required a ''more radical, root-and-branch overhaul''. He challenged the low rate of substantiation of complaints recorded by CAPO. ''In 1992, the rate of substantiation of complaints was an incredible 0.7 per cent. Either the 1,902 complainants in 1992 were all liars, or there is something wrong with the system,'' he said. Those who supported Mrs Lam said it would be dangerous to overhaul the system during the transition period. Mrs Lam warned that an independent CAPO would undermine the confidence of the police force. ''The formation of an independent complaints body will deal a hit to the morale of the police. They will see this as an open display of the lack of confidence in them.'' She was backed by the 14-member Liberal Party. The party's Mr Stephen Cheong Kam-chuen said the introduction of drastic changes to the complaints system would undermine the stability of society. Another Liberal Party legislator, Mrs Selina Chow Liang Shuk-yee, wanted to know whether it would be appropriate to have laymen replace the expertise in the present police complaints inquiry system.