For 18 hours on March 2, 2002, Wallace was pinned down in Afghanistan's Shahi Kot valley with a fellow SAS trooper and 80 US troops in one of the fiercest battles involving Australians since the Vietnam War.

While much of the Australian military's fighting in the war in Afghanistan is shrouded in the secrecy, Wallace has lifted the lid on his experiences to give future generations of soldiers an honest chronicle of what the fighting was like.

"I wanted younger soldiers to have a realistic contemporary account," the quietly-spoken former soldier, who was given the Medal for Gallantry for his actions in the battle, said yesterday.

His account of Operation Anaconda in Afghanistan has formed the basis of a book by Australian journalist Sandra Lee. The book Eighteen Hours tells of how Wallace risked his life to save wounded US soldiers fighting alongside him, knocked out an al-Qa'ida machinegun post and served as a communications lifeline after the unit was ambushed by a larger force.

"I wouldn't describe it as brave," he said. "It was do or die."

As a signalman, Wallace provided a vital communications link to Australian and US commanders controlling the Bagram airbase, calling in airstrikes on approaching rebels.

At one stage Wallace pulled out a grenade, armed it and lay on it to boobytrap his body in case his position was overrun by Taliban fighters.

The operation was supposed to have mopped up the remnants of al-Qa'ida and the Taliban in that part of Afghanistan. But poor intelligence underestimated the number of enemy combatants, leaving 200 coalition troops to face 1000 fighters who controlled the high ground.

As one of two Australian liaison officers, Wallace landed in a Chinook helicopter with 80 troops from the US Army's 10th Mountain Division.

The division was immediately pinned down by enemy machinegun, rocket and mortar fire. About a quarter of the troops were injured, some seriously, but miraculously no one was killed.

The group was airlifted out under cover of darkness moments before enemy fighters overran their position.