A mistake in the consultation document on proposed new terrorism laws has let slip crucial details of government concerns.
By using the 'track changes' function recipients were able to see the modifications that had been made when the document was being written.
For example, in the original draft Home Secretary Charles Clarke expressed doubts about extending the length of time police officers could hold suspects: "The case for some extension is clear, though I believe there is room for debate as to whether we should go as far as three months. I'm still in discussion with the police on this point."
But this paragraph was excised from the final document.
Speaking at the Liberal Democrats conference yesterday party leader Charles Kennedy expressed serious concerns about the "three months" figure, stating that it was too long and that his party would be raising questions over the issue.
Joe Fantuzzi, chief executive at document specialists Workshare, said: " Today's Terrorism Bill gaffe is another example of how a lack of awareness of hidden document information can cause major embarrassment and loss of credibility.
"Even after the Dodgy Dossier incident in 2003, the public sector still does not appear to have got the message that while email is undoubtedly an excellent medium for communicating with documents, it opens up huge exposure to security and control issues.
"Our own research shows that up to 75 per cent of business documents can contain sensitive information most people would not want exposed, with a further 90 per cent having no idea that confidential information was being leaked."
This is not the first time that similar mistakes have been made. In May the US Army accidentally released classified information into the shooting of Italian intelligence agent Nicola Calipari in a PDF document.
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