Wednesday 8th August 2018 marks the hundredth anniversary of the start of the last hundred days of the first world war. Although the Hundred Days Campaign didn’t actually last 100 days, it was five days short!

The last hundred days are a little studied period of the war, and that’s a shame because they represent the high point of the transformation of the British Army. In 1914 there were 100,000 regulars organised as an Imperial expeditionary force. By August 1918 there were millions of men under arms operating in a recognisably modern fashion in large scale operations.

Mobile combined arms, not mud and blood

The last Hundred Days was fluid, evidenced by the use of trucks, cavalry and tanks.
Canadian vehicles preparing to move forwards during the Battle of Amiens 1918 (photo: Yukon Archives, Canada)

There is a totally different narrative, Britain was the main participant in the allied campaign. Three British Armies (which included Australian, Canadian, Indian and other imperial contingents) fought alongside two French and one American armies.

The battles were combined arms affairs involving armour, artillery and air support for the infantry. They were also mobile, with advances governed by the depth of artillery support and how far an infantryman could walk across the battlefield. Casualties were much lower too.

The Last Hundred Days

This is the period where the first world war stopped being a static trench war of attrition and became mobile again. Attrition had hollowed out the French, they took the worst of the casualties. It had a similar effect on the Germans, but the collapse of the Russians at the end of 1917 gave them fresh troops to commit to the Western Front.

Early 1918

The start of 1918 was a race for victory. The previous year had seen the French army rendered ineffective through widespread mutinies and the loss of too many men that it just couldn’t replace. Britain was also suffering manpower shortages, but had introduced conscription and had reserved to draw on.

The Russians collapsed under two revolutions and signed a separate peace treaty at Brest-Litovsk. This took them out of the war and gave the Germans a secure flank that they could redeploy troops from.

The Americans started to arrive in small numbers in late 1917 and had a million men in training ready to ship to France.

So the Germans had a brief chance to strike a hammer blow to knock the French out before the Americans arrived in numbers. They launched the Michael Offensive in March, and it moved the front dramatically, but it was too little too late. Four US Divisions and dozens of British ones stabilised the line.

US Contribution to the Last Hundred Days

The American army was starting to arrive in numbers, but lacked experience. It only started to operate as a formed army in late August 1918, although US troops had seen combat under French and British command before then. Seven US Divisions fought under General Pershing in the Hundred Days Campaign.

First Day of the Last Hundred Days

German prisoners march into captivity at the start of the Hundred Days campaign. (photo: Imperial War Museum)

A good example of how the British Army had developed is the contrast between the first day of the Battle of Amiens in 1918 and the 1916 Battle of the Somme.

In 1916 the British Army was effectively a novice organisation. It hadn’t done anything on that scale before. Lots of planning and preparation went into the battle, the staff weren’t novices, but the front line troops were. The story is well known.

In 1918 ten Allied divisions in the British Fourth Army with 500 tanks attacked the Germans just south west of the 1916 battles. There was a fifteen mile wide gap in the German lines. Troops advanced almost 12 miles. With three days they’d recovered all the ground lost during the German offensives in March to June. That was a greater area than the entire 1916 battle. British casualties were a tenth of 1st July 1916. The Germans lost over 30,000 soldiers and saw it as a black day. Their morale collapsed and they started to withdraw onto the Hindenburg line.

Widening the Front

A tank pushes forward as prisoners carry the wounded to the rear (photo: IWM)

Less than a fortnight after the Battle of Amiens the British Third Army started the Battle of Albert. This was over the old 1916 battlefield, but it went quite differently to that battle. The British Third Army pushed the Germans back along a 34 mile wide front. The French did the same immediately to the south. First Army joined in a few days later and did the same to the north.

The war had become fluid, and by early September the Germans were back on the Hindenburg line. The British, French and American armies closed up to them. The British Army had the biggest contingent in the battle, although more Americans would feed in as they arrived.

Breaking the Hindenburg Line

The Hindenburg line near Bullecourt from the air. (photo: wikimedia)

It took the Allied armies three weeks of planning and bringing up supplies and reinforcements to take on the Hindenburg line (which was the British name for it, the Germans had called it the Siegfried Position). The pause wasn’t a complete return to static lines because salients were pinched out.

In the last week of September the offensive resumed. It took the French and American armies until 17 October to break through the Hindenburg line in the south. In the centre the British Fourth Army and French First Army did rather better. They broke through the entire depth of the Hindenburg line over a 19 mile front by 5th October. Three days later the British First and Third Armies also broke through the entire Hindenburg line on their fronts.

From this point on the battle became mobile. The Germans were pressed East and forced to abandon heavy equipment. Many rearguard actions happened, and a handful of set piece large battles. However the German Army was comprehensively defeated in the field.

The Price of Victory

War has a cost, and the last hundred days were little different. However overall they were less bloody than earlier offensives. Many prisoners were taken, and the fluidity of advance meant that many attacks were made against hastily defended positions. Once the Hindenburg line was breached the Germans had little time to dig in and prepare before the next attack.

Still, a million Allied soldiers were casualties, and the Germans lost 785,000 casualties and another 386,000 taken prisoner. Modern warfare was just as deadly when it was mobile as it was static.

Further Reading on the Hundred Days Campaign

We don’t get taught about the Hundred Days campaign, and we should be. It’s the counterpoint that explains how we won the war and militarily defeated the Germans. There’s a myth, that fed the nazis rise to power, that the German Army wasn’t defeated but was stabbed in the back by the politicians. This isn’t true. Here are some books that can tell you more about that.

All the links go to the paperback versions on Amazon UK.