Vanunu served his sentence at Shikma Prison in Ashkelon, where he was held in administratively imposed solitary confinement. On May 3, 1989, he appealed his conviction and sentence to the Israeli Supreme Court and was brought from prison in a closed police vehicle to the Supreme Court for an appeal hearing. In 1990, his appeal was rejected. The following year, an appeal to the Supreme Court arguing for better prison conditions was also rejected. On March 12, 1998, after having spent over eleven years in solitary confinement, Vanunu was released into the general prison population. While in prison, Vanunu took part in small acts of defiance, such as refusing psychiatric treatment, refusing to initiate conversations with the guards, reading only English-language newspapers rather than Hebrew ones, refusing to work, refusing to eat lunch when it was served, and watching only BBC television. "He is the most stubborn, principled and tough person I have ever met", said his lawyer, Avigdor Feldman. In 1998, Vanunu appealed to the Supreme Court for his Israeli citizenship to be revoked. The Interior Minister denied Vanunu's request on grounds that he did not have another citizenship. He was denied parole because he refused to promise that he would never speak of the Dimona facility or his kidnapping and imprisonment.