31-year-old car parts manager Martin Dunn discovered the device as he was searching for computer spare parts at a rubbish tip in Winchester, Hampshire. A woman handed Dunn a bag containing the laptop and a booklet outlining armed forces security procedures.
The computer is alleged to contain 70 files detailing plans to deal with terrorist attacks on an army camp and navy base in the UK. The files are said to contain maps and plans of local military and naval bases. An MoD spokeman said it had started inquiries to find out whether or not the laptop and booklet was official MoD equipment.
"At the moment we are not clear whether this is official equipment as sometimes staff are allowed to use their own equipment," an MoD spokesman told PA.
"Ordinarily we have procedures in place to ensure that equipment being disposed of doesn't contain restricted information."
Security experts were quick to point out that MoD policy forbids the use of unencrypted data on mobile devices.
"It is MoD Policy to roll-out full disk encryption onto every laptop," said Peter Jaco, CEO of encryption company, BeCrypt. "This incidient looks very suspicious to me. It is very unlikely the MoD would dispose of laptops in this way."
Jaco added the MoD has very strict policies on how data is protected and can only use encryption products approved by the Communications-Electronics Security Group (CESG).
Earlier this month SC Magazine reported that a hard drive full of German government secrets ended up being auctioned on eBay.