The Hidden War

A definitive history of the men who faced darkness, danger, and the constant threat of being buried alive.

Far below the trenches of the Western Front, where darkness pressed against timber and clay and every sound carried the threat of death, Australian tunnellers waged a war few have heard, and even fewer can imagine. Working in suffocating heat, stale air, and crushing claustrophobia, these men carved out living quarters, supply chambers, and attack tunnels—sometimes only inches from German diggers doing exactly the same. One wrong tap of a pick or a single explosive charge could bury them alive without warning.

The Hidden War is the first complete and meticulously researched history of Australia’s tunnelling companies from 1914 to 1919. Drawing on personal accounts, operational files, and years of detailed investigation, Damien Finlayson reveals the scale, science, and nerve of this underground conflict: the clay-kickers and miners who pushed towards enemy lines; the engineers who calculated blast strengths and shaft supports; and the teams who wired vast underground mines that shaped battles at Fromelles, Arras, Messines, Passchendaele, Cambrai, the Lys, and in the defence of Amiens.

Finlayson situates the tunnellers’ work within the broader machinery of the Great War, showing how their labour underpinned some of its most decisive operations. He also writes with empathy for the men themselves—their gallows humour, their camaraderie, and the psychological strain of serving in a place where the ground could turn traitor at any moment.

Long overlooked in Australian military history, the tunnellers emerge as ingenious, disciplined, and extraordinarily brave. This is a powerful, authoritative account—rich with technical insight yet fully alive to the human cost—of a war fought in darkness, silence, and earth.

‘Highly detailed and intricate… he has done the ANZAC tunnellers proud.’ — Dave Wilkins