20–21 November 1917

This British Mark IV tank was destroyed by German fire during the Battle of Cambrai in November 1917. Tanks were still in their infancy in 1917 and could be disabled without great difficulty.

The tank is one of the most significant inventions in modern war, but it took some time before the primitive and slow contraptions built during the First World War developed into the fast, heavily armoured, battle-winning vehicles of the wars that followed. Combined with battlefield aviation, the tank brought a renewed flexibility and striking power to modern armed forces. The first time the tank-air combination was used was at the Battle of Cambrai on the Western Front in November 1917, when the British attempted to unhinge the apparently impregnable German defences of the Hindenburg Line. It was not an entirely auspicious start, but nonetheless it marked the advent of a new age of war.

The tank was developed through the efforts of a number of ingenious naval and army officers who saw that the stalemate of trench warfare would only be broken by technical or tactical innovation. The British War Office was sceptical when first shown the clumsy tracked vehicle, but with the support of the Minister of Munitions, David Lloyd George, the first forty Mark I tanks were ordered, and by May 1917 they were organized into the Tank Corps under the command of Lieutenant Colonel Hugh Elles. Doctrine for the tanks’ use emerged piecemeal, but all those involved in their development recognized that their impact would only be achieved en masse.That was not how the first few tanks were used. The new British commander-in-chief, General Douglas Haig, wanted them to support his massive assault on the Somme, which began in July 1916. A total of forty-nine Mark I tanks were used for the first time on 15 September in small packets, but despite the initial shock caused to the German defenders, the tanks were knocked out by shellfire or disabled by mechanical failure.

Haig was sufficiently impressed to order 1,000 more, but it was not until the late summer of 1917, after the failure of the Passchendaele offensive, that they were used in larger numbers. On muddy, cratered ground the tanks had made little progress. They moved at only around 3–5 km/h (2–3 mph) and once immobilized were an easy target for enemy gunners or for German riflemen armed with new armour-piercing bullets. Elles tried to persuade Haig that tanks needed to be used en masse and on ground suitable for tracked vehicles.The new Mark IV tank was faster, with better armour, and had a more advanced track design. At Cambrai, near the River Scheldt in northern France, the ground was sufficiently firm and flat and the sector was held by seven weak German divisions. Elles suggested using the British 3rd Army to mount a major raid towards Cambrai with a large body of tanks supported by aircraft. Haig, desperate for positive news, finally agreed.

A force of 474 Mark IV tanks was assembled in great secrecy on the Cambrai front. They were brought in by rail and concealed in woods and sheds. To be sure of crossing the wide trenches of the Hindenburg Line, each tank carried in front a huge bundle of wood, or fascine, to be dropped into the trench so as to allow the tank across. Elaborate tactics were worked out. Infantry would follow the tanks, and between them they would carve out a gap in the line for British cavalry to move through and capture the German forces from the rear. This bizarre mix of old and new had a symbolic feel to it. Tanks were slow and potentially deadly, but horses were fast and flexible; yet the tank had a military future to it, while the days of the cavalry were numbered. The operation was ready by 19 November 1917, after weeks in which every effort was made to prevent alerting the Germans.

German soldiers lie dead on the wooden duckboards of their trench following a British attack at Flesqières on 23 November 1917 during the Battle of Cambrai. The early British gains were not exploited effectively and much of the captured area was soon back in German hands.

Thus the enemy was caught almost completely by surprise when, on the early morning of 20 November, columns of tanks lumbered out of the morning mist, led by Elles himself. All along the line the Germans sent up SOS rockets, adding their bright lights to the flashes of shells bursting from the tanks, and from the British field artillery firing over them at the retreating Germans. One tank would patrol a trench, firing at the soldiers inside, while a second one dropped its fascine into the trench. After it had crossed, this tank patrolled the far side of the trench while the first tank got across. The infantry followed, mopping up the few dazed German defenders. The dense walls of barbed wire were crushed by the tanks, some of which were tasked with rolling the wire into giant balls to clear the ground for the expected cavalry attack. Inside the tanks, the crews of ten struggled with the noise, the fumes, hot shards of metal from shell impacts, and the unbearable heat. A direct hit from a German shell could turn the tank into an inferno in which the men were roasted alive. Overhead the Royal Flying Corps, with 275 fighters, bombers and scouts, harried the small force of 75 German aircraft, many of which were lost in the poor weather as they tried to find the front line. Within hours the tanks had forged a salient 8 kilometres (5 miles) deep and 10 kilometres (6 miles) wide towards the town of Cambrai and had breached the Hindenburg Line, capturing 8,000 men and 123 guns. The scene was set for the first tank victory.

In the end it was not to be. The Germans fought boldly back and were soon reinforced by reserves. Key geographical points proved difficult to capture, particularly the Flesquières Ridge overlooking Cambrai, where a legendary German artillery officer had single-handedly knocked out five tanks before being killed. Tanks broke down or were destroyed by accurate fire. By the end of the day, there were only 195 tanks left, many of these needing mechanical overhaul. Above all, the key lessons of tank warfare had been ignored. The infantry were not quick enough to exploit the breakthrough achieved by the tanks, while the cavalry were held too far back and failed to rush through the gap created by the tanks until it was too late.

In London, news of the day’s fighting was greeted with jubilation. But the following day the advance slowed, losses mounted and German reinforcements began to appear. Over the week that followed, German forces reversed the British gains. A few of the remaining tanks, just 38 from the original force, prevented the British salient from being eliminated by a flanking attack – showing what potential the tank still had – but by early December most of the ground gained had been lost. Each side suffered losses of around 45,000 men, and the brave tank crews suffered casualties of 29 per cent of their original number. The battle, despite its eventual failure, marked the arrival of the tank as a battlefield weapon. On the same ground a quarter-century later, the German army demonstrated what it had learned from the lessons of Cambrai.