Soon after dawn on July 1, 1916, British and Commonwealth troops climbed out of damp, muddy trenches in the Somme valley and began to advance across no-man’s land toward German positions. This was the biggest Anglo-French attack of the First World War to date, and British commanders were confident that their troops would quickly push the Germans back out of France and perhaps even begin a drive into Germany itself. The tactics they used in planning this battle had changed little since the Napoleonic Wars. After an artillery bombardment, a mass of infantry would move forward to overwhelm the defenses, and then three cavalry divisions would exploit the breakthrough and drive deep into German-held territory.

The British commander, Field Marshal Douglas Haig, was certain that this battle would lead to a decisive victory. The Germans had been worn down by fighting on other parts of the Western Front in 1915 and the British attacking force was one of the largest bodies of men at arms ever sent on the attack. However, by the time that night fell on that day, 57,000 British troops had become casualties, including more than 19,000 killed, the highest number of British casualties in a single day of combat.

Nevertheless, over the course of the following 140 days, this plan of attack was repeated again and again. By the time that winter weather made further attempts impossible, more than one million men had become casualties on this short stretch of the Western Front, and at no point had British troops managed to advance more than a few miles into German territory.

A year later, on July 1, 1917, Haig attempted the same tactics at Passchendaele, near the city of Ypres in Belgium. By the time that attack finally petered out, more than 400,000 British troops had become casualties for the gain of very little ground. Haig, previously well-regarded as a military leader, became known in the Royal Army as “the Butcher”.

What Haig and most other military commanders on all sides during World War I failed to grasp was that infantry tactics in use for more than a thousand years were no longer viable. That was simply because sending massed infantry formations to attack prepared enemy defensive positions could no longer succeed in the face of machine guns, which could pour a devastating stream of fire on any exposed troops. Sending troops over open ground to attack a defense that incorporated many linked machine gun positions was simply suicidal, and the outcome was carnage on an industrial scale as more and larger attacks during World War I simply caused even larger numbers of casualties.

What made the slaughter even more sickening was that the machine gun was hardly new in 1916. The first reliable and functional machine gun entered military service in the early 1860s, more than 50 years before the terrible slaughter in Western Europe, yet no military leader seemed to have considered the fundamental impact that this weapon might have upon land warfare.

In fact, in The Machine Gun, a four-volume work authored by a former US Marine, Lieutenant Colonel George M. Chinn, it is claimed that machine guns have been responsible for the deaths of more people than any other device. Chinn asserted that 92 percent of all combat casualties caused during World War I were attributable to machine guns, and that these weapons may have directly caused the deaths of more than eight million people around the world since the introduction of modern machine guns in the 19th century.