CLASSIFIED Ministry of Defence and Nato computer files were found dumped in a skip. Two Newport workmen discovered the five stripped-down computers in their skip when they returned from a coffee break.

Now defence chiefs are investigating how the potentially sensitive information came to be on the discarded computers.

The two contractors, who asked not to be named, were working at the University Hospital of Wales, Cardiff, on Saturday afternoon when they made the discovery.

One took home a hard drive, which stores all the computer's information, hoping it would provide him with extra space on his own machine.

But, when he plugged it in to his own computer, it revealed Royal Air Force files. The files - authenticated by the military after the Argus provided copies - included details of accident reports from as far back as 1998. One file contained the ranks, names and telephone numbers for several high-ranking servicemen.

The workman told the Argus: "I couldn't believe it when we found the computers there, I know computers backwards and there is always stuff being dumped that I know I can use. "I would have thought the MoD would be more careful with a war on."

He added: "There were five files in English and when I saw what was on them I was terrified - each one said 'Security Classification - NATO RESTRICTED' all over them. "Things like this could be used for blackmail, especially at this sensitive time."

Among the files are some reports of incidents involving faults to planes. One, from October 1998, concerned a 'ground incident' with a Harrier aircraft and revealed bolts securing some doors were missing.

The report concluded: "Analysis of a recovered bolt revealed that it had fractured. BAE REP at RAF Laarbruch was contacted and revealed that similar problems have occurred previously on other aircraft."

The Argus has advised the two men to formally report their finds on to the Ministry of Defence immediately.

A Ministry spokesman said: "We take matters like this extremely seriously. "Once it has been formally reported we would obviously seek to conduct a thorough investigation into what information is on the hard drive and how it came to be found."