Reports from news service Reuters initially said that the Ministry barred all portable storage devices because they threatened sensitive data.
But the MoD has said the devices have not been totally banned.
"That story was kind of an exaggeration," said Andy Campbell, managing director Reflex Magnetics, a firm that supplied the MoD with encryption for its mobile devices. "They are pragmatic and will take whatever security measures are necessary for their networks. A restricted network will have the security needed.