British military secrets held in portable computer drives have gone missing, the Ministry of Defence has admitted.
This year, 22 portable memory sticks containing classified information had been either stolen or lost, the MoD said.
More than 700 MoD laptops have gone missing or been stolen in the last four years.
The disclosure sparked claims that the Government has not learned from previous Whitehall information-handling blunders.
Earlier this year, an independent review of the MoD's information security systems warned that a "Facebook generation" of young officials had not learned the disciplines of the Cold War and were often careless with sensitive data.
In a written parliamentary answer, the MoD said that 131 of the department's portable USB memory sticks had been taken or misplaced since 2004.
Twenty six of the small storage devices have been lost this year. Three of those held information classified as "secret." Another 19 carried "restricted" data.
The MoD also said that between 2004 and 2007, a total of 658 laptops were stolen, and another 89 were lost. Only 32 have been recovered.
Previously the MoD had confessed to 347 laptops being stolen, but the total was raised after "anomalies in the reporting process" were discovered.
USB memory sticks are only a few inches long and easily fit in pocket, but they can store tens of thousands of computer files.
Many IT security professionals advise that their use is carefully controlled in sensitive sites, because they can easily be used either to steal copies of files.
Intelligence agencies including MI5 screen visitors to their buildings for USB sticks and tightly limit their use by staff.
The MoD figures were obtained by Sarah Teather, a Lib Dem MP.
She said: "It seems that this Government simply cannot be trusted with keeping sensitive information safe.
"It is frightening to think that secret MoD information can be lost or stolen."
Liam Fox, the Tory shadow defence secretary: "This is yet another example of the Government's inability to protect confidential information. To treat national security in such a cavalier fashion is unforgivable."
The MoD said: "Any loss of data is investigated fully.
"The recent report on data losses by Sir Edmund Burton found that MoD policies and procedures are generally fit for purpose, but also identified a number of areas where MoD needs to do better in protecting personal data.
"MoD has developed, and is now working through, an action plan to address all of the report's recommendations and bring the department's handling of personal data to an acceptable state."
Source: THE TELEGRAPH UK