The original is no longer available, but the redacted PDF is here. Via Yahoo News:
A “technical error” has caused Britain’s Ministry of Defense to inadvertently publish classified sections of a report containing sensitive information about US Navy and British military nuclear submarines, the BBC reports.
Sensitive information in the report, which was published to Parliament’s website after a Freedom of Information request by anti-nuclear campaigners, includes how much structural damage British subs can take before a full meltdown takes place, as well as US vessels’ abilities to handle nuclear core failure.
The “schoolboy error,” as the MoD has called it, was due to improper redaction in the PDF document. As British tabloid the Daily Star Sunday, which first reported the gargantuan slip-up, points out, “anyone wanting to read the censored sections just had to copy the text.” This was most likely because whomever attempted to redact the document did so with the digital black highlighter, which simply covers up, rather than fully redacts, the text in a PDF.
