Sandbags were invariably used to provide troops with protection at both the front and rear of trenches (the parapet and parados) and were generally stacked some two or three feet deep.

Such sandbags - filled with earth by regular filling parties - afforded troops manning the trench fire-step with effective protection from enemy rifle fire.

Sandbags were however rather less useful in offering protection from the effects of artillery shellfire, although sandbags piled at the rear of the trench did protect to some extent from the back-blast of shells which commonly fell beyond the trench line.

Photograph courtesy of Photos of the Great War website.