The government is trying to have what is believed to be a top secret MI5 document, removed from the Internet over fears it could endanger the lives of covert field operatives, according to a US ISP. The document, "Libyan Intelligence Service activity in the UK", which purports to contain details of recent surveillance on Libyan intelligence officers in the UK, was published on a US Web site on Sunday April 16. The document is believed to reveal the identities of a number of covert MI6 and MI5 officers working in Libya. It is classified "Top Secret Delicate Source UK Eyes A." The classification "UK Eyes Alpha" means the document is restricted even from co-operating intelligence services such as the CIA. The government has reacted quickly to quell interest in the document: the D-Notice committee has requested that details of the site not be published. The Florida ISP which hosts the Web site where the material has been published, says it was contacted on Tuesday April 18 by representatives from an undisclosed "British Intelligence Agency" and asked to remove the document from its servers. According to the ISP, these representatives claimed the document is highly sensitive to Britain's national security. A spokesman for the ISP said: "Our legal department was contacted by the British authorities and it was requested that we ask a customer to remove the page because of its sensitive nature. They didn't go into detail about that sensitive nature." The Web site owner who published the document has, however, refused to remove the material, despite his ISP's request to do so. Instead he has issued a statement: "I do not believe that posting the document is illegal under US law." It continues: "An informal request, not a court order, is insufficient reason to remove the document which provides significant public information." On Friday the owner of the site confirmed to ZDNet UK that the document was sent to him anonymously. He also claims to have received no further communication from his ISP or from any representative of the British government. Regarding who contacted his ISP, the owner said: "I don't know whether it was someone from the British Government or the US government acting on their behalf." The Independent newspaper reports Monday that the intelligence services have blamed the leaked document on former MI5 officer David Shayler. According to the Independent, Shayler denies responsibility for the leak but says that this represents the most serious breach of government security yet. On Friday the Home Office refused to comment on any specific security services issue. The same refusal was issued Tuesday morning. What do you think? Tell the Mailroom. And read what others have said.