The image of the western front campaign is of a trench-bound stalemate, with millions dying fighting over a few metres of mud. Sometimes it was all too true, but in 1918 it changed into an astonishing drama, with huge swathes of territory lost and won and the war's outcome being in perilous balance.

The prelude

Artillery barrages helped both the Germans and the British to advance

The year 1918 dawned on a shattered Europe after a dreadful 12 months. France's still exhausted army had been on the edge of mutiny following huge losses; Britain's offensives had, after a bright opening, bogged down in the Passchendaele mud; Germany had been bled white halting Allied attacks.

But Germany knew its own resources were declining irreversibly, while America's entry into the war would strengthen the Allies. In a desperate last throw Germany launched a series of offensives to win the war before the Allies became too strong.

They carefully applied the lessons of previous years. For instance large numbers of specially trained stormtroopers were used to infiltrate Allied positions, so there were no lines of soldiers to machine gun down, and more importantly the Germans orchestrated the war's most devastating artillery bombardment.

The German assault

On 21 March they launched Operation Michael against the British. Instead of days of artillery preparation, as before in the war, there was a five-hour storm of highly accurate fire from 6,000 guns, that surprised and devastated their opponents. Then a million German soldiers attacked along a 50-mile front.

The British defences were not a simple line of trenches, but used "defence in depth" with a whole series of positions to gradually slow the Germans down, like a shock absorber. However many British units were undermanned and overstretched. With their defences destroyed by artillery, heavy fog added to the confusion of the shocked survivors who were quickly overwhelmed.

The Germans advanced 40 miles, a previously unheard of figure, but gradually the British forces, fighting with desperate courage, slowed them. Finally, with their supply lines overstretched the exhausted Germans ran out of steam, having lost many of their best troops.

Then the Germans quickly followed up with further massive offensives against the British and French, Operations Georgette and Blucher on 9 April and 27 May. With real fears the war could be lost the British commander, General Douglas Haig issued a special order concluding: "With our backs to the wall and believing in the justice of our cause, each one of us must fight on to the end."

But these attacks, despite early success, finally petered out in late June, and although the Germans had gained ground it was at a fatal price, and the entry of US troops into active fighting symbolised the German race against time had been lost.

The Allies reply

Tanks played a key part in the British victory of 1918

Within a month, from mid-July, the battered Allies, sensing the tide's turn started the offensives that won the war. Success was so unexpected it was hard to stop planners preparing for war in 1919.

On 8 August the British, supported by the French, launched a remarkable surprise attack that showed they too had learnt the lessons of previous campaigns. Masses of troops were moved secretly to attack on the heels of a large-scale tank assault, backed by an artillery barrage as devastating as anything the Germans had managed.

The German commander, General Ludendorff wrote: "August 8 was the black day of the German Army. Our war machine was no longer efficient."

It was recognition his army had not just been thrown back, but many soldiers had quickly surrendered or run, indicating a declining will to fight.

But while the Germans were fading they could still fight hard using formidable prepared defences like the Hindenberg Line. Nevertheless, at great cost the Allied advance was steady, with British assaults often led by Canadian or Australian forces, who were regarded as elite attacking troops. By the Armistice the Allies had advanced up to 50 miles

The lessons

The campaign of 1918, often overlooked compared to other campaigns such as the Somme, helps give a more balanced perspective on the war.

The same British generals, so often labelled "donkeys" because of previous failures, commanded the final offensives with considerable competence. The events of 1918 also suggest the bloody stalemate of previous years was mostly inevitable because the technology and training needed for this new kind of warfare was still developing.

It also has to be asked if the 1918 victory could have happened without the war of attrition that wore the Germans down.

Casualty figures tell their own story about this most terrible war. The victorious British advance in 1918 created a higher daily casualty rate than the 1916 Somme campaign, while the German success of 12 March produced 40,000 dead, wounded and missing - about the same as their defeated opponents.