They were young, they were Australian, they were Army engineers and they were the first allied soldiers to risk their lives in the darkness of the Vietcong tunnels of South Vietnam. Not only did they follow their enemy down into these unknown underground labyrinths, but matched the Vietcong's jungle warfare skills and defused thousands of their clever booby traps.Off duty, it was a different story. The bad boys of 3 Field Troop were a boozing, brawling, bonking bunch of larrikins, who cut a swath through the bars and brothels of Saigon, fought American Military Police to a standstill, built a secret casino and booby-trapped their own HQ to teach their officers a lesson.