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According to the Telegraph: The plans for the new building included details on alarms, emergency exits, wall thickness and the locking systems designed to protect the 4,000 personnel who will work there. Focus also said the blueprints could have been missing for a year before anyone noticed their absence. (more)
Oh, like this has never happened before...
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The lost 66-page dossier of floor layouts—once used by trusted CONTRACTORS at the high-security Central London base—would be gold dust to terrorists.
The plans were given to us by a worried member of the public, who got them from a friend who worked at the building and never handed them back. (more)