The US' Homeland Security Department has made the nation only marginally safer than before the 2001 terror attacks that created it, the agency’s former internal watchdog claims in a new book.

Undercover government investigators smuggled explosives and weapons past security staff at 15 airports in the US, it emerged today.

AIR MARSHALS have been caught sleeping on the job, have lost their weapons and tested positive for drugs and alcohol, according to a new report.