The Ministry of Defence (MoD) is refusing to respond to Parliamentary questions, tabled in late October, which revealed that nearly 600 computers had disappeared from the department in the last five years, according to a Liberal Democrat MP. Figures obtained by the Paul Burstow MP show that government computer systems were infiltrated by hackers on at least 64 occasions in the last five years. A total of 1,354 government-owned computers also went missing in the same period. But the MoD, whose systems have been subject to at least 27 hacking incidents since 1995, is withholding its response to related questions posed by Burstow last year, he said. "The MoD was asked about this in late October, and still hasn't replied," said Richard Stokoe, assistant to Paul Burstow MP. "With Parliamentary questions you have a total of two weeks to respond, but (the MoD) has said that it is waiting for central office approval. There is a possibility that the figures could be worse than they were two years ago." Besides the public expense entailed by lost computer hardware, missing government computers could pose national security issues. MI5 has also come under criticism for allowing laptops containing sensitive information to be lost or stolen. Burstow tabled the same Parliamentary questions on cybercrime and computer loss to government departments two years ago. His intention was to discover how well the government was looking after its "machinery". Computer theft has become a serious problem for some departments, according to Burstow's findings. Over the last five years, 419 computers have been stolen from the Department of Work and Pensions -- 42 in 2001 alone. The MoD also lost 594 computers in the same period, the Department of Trade and Industry 79, the Lord Chancellor's Office 77, and the Cabinet Office 43. "I do not think the answers I have received give the full picture," said Burstow. "The figures beg the question: are departments that say they have not detected evidence of illegal access just victims of more sophisticated hackers? There must be a critical examination of UNIRAS (Unified Incident Reporting and Alert Scheme) reporting to ensure that there are no blind spots." The MoD downplayed the extent of the problem. "We can't argue with these figures, but it was 594 items of computer equipment stolen, rather than 594 computers," said a spokeswoman for the MoD. She said that the department's lack of a response to a Parliamentary question doesn't necessarily mean anything. "It wouldn't be out of the ordinary for us not to respond to this question," she said. "It depends on the type of question, and we often put in holding replies." See the Net Crime News Section for the latest on hacking, fraud, viruses and related issues. Have your say instantly, and see what others have said. Click on the TalkBack button and go to the Security forum. Let the editors know what you think in the Mailroom. And read other letters.