In May 1916 Major Eustace Lockhart Maxwell, a former Indian cavalry officer, was given command of an infantry battalion in France. After 48 hours with his new unit, Maxwell wrote to his family: 'The outstanding characteristic of those who belong to it seems to be their extraordinary self-complacency Esprit de corps is a fine thing, but the satisfaction with which they regard themselves, their battalion, its internal economy, its gallantry, its discipline,...