A SHANGHAI dissident, who was illegally detained by police for more than a month, has been demoted by her work unit for a ''grave political error''. Ms Fu Jiqing, 47, was detained on March 1 for allegedly ''colluding with hostile overseas groupings'', specifically Mr Wang Ruowang who is based in New York. Police alleged that Mr Wang, who was thrown out of the Communist Party on the personal orders of patriarch Mr Deng Xiaoping, had asked Ms Fu to ''spread the message'' of the pro-democracy movement. Until her release last week, Ms Fu was not formally arrested or charged, which is a violation of China's judicial procedures. Friends of Ms Fu, a college-trained engineer, said she was shocked to learn that she had been demoted to ''ordinary worker'' on returning to her job at the Shanghai Reform Electrical Machinery Factory. ''Officials in our personnel department told me that because of my political error, I am no longer fit to be a cadre,'' she said last night. ''Communist Party authorities in the factory will soon make a decision on the margin by which my wage and bonuses will be cut.'' Ms Fu, a good friend of Mr Wang's wife, had been warned not to communicate with the Wangs on her release. ''I shall draw a clear line between myself and Wang Ruowang,'' she said, meaning she would stop talking or writing to her friend. ''It may be better that way.'' Former journalist Sun Lin, 36, detained with Ms Fu, has still not been released.