A contributory cause of the comparative failure of the Franco-British plan of campaign in 1917 was the want of perception of the intention of the Germans to withdraw from the positions in the Somme area which they had defended so stubbornly in 1916, and which the Allies were preparing to render untenable or to batter down. The want of perception was not complete, but both British and French plans were upset by the suddenness and extent of the withdrawal, which the Germans effected with much less loss than they should have been forced to sustain. The first symptom of the general withdrawal was discovered in March, when portions of St. Pierre Vaast Wood, near the junction of the French and British lines, were found to be evacuated. By 17th March the German voluntary retirement was in full swing, and their forces ruined everything as they retreated. By 17th March, also, the British front from Roye to Arras was moving forward, and on 2nd April the Fifth Army was within two miles of St. Quentin, while the Fourth Army on 5th and 6th April was at Ronssoy and Lempire. While the British armies were pushing towards the Cambrai-St. Quentin line the French were pushing on a 30-mile front from the north of the Upper Somme, towards the new German line from St. Quentin, behind Soissons, in front of the St. Gobain plateau, the Forest of Coucy, and the Chemin-des-Dames. Behind the new line Nivelle matured reconstructed plans for the great French attack towards Laon.
Of the new fortress line (the Hindenburg and Drocourt-Quéant line) which the Germans had constructed and continued to improve, the La Fère-Laon position and the Chemin-des-Dames were the southern bastion, and the Vimy Ridge the north-western pillar. Sir Douglas Haig's preconcerted plan had been to attack the Arras front, not in order to assault this line, but as preliminary to the Ypres salient thrust farther north. Nevertheless, the plan could be adapted and it was prosecuted. Preparations on a large scale, equivalent to building a counter-fortress front, had been made for the Arras operations, and the greatest precautions were taken to lend the attack all the support which mines and artillery could give. Two armies, the First (General Horne) and Third (General Allenby), were prepared for this action. Horne's army made its attack on the Vimy Ridge, with the Canadian Corps as shock troops, on 9th April, and the attack was extended on a 12-mile front from Hénin-sur-Cojeul, south-east of Arras, to Givenchy-en-Gohelle, north of Arras. The Canadians took the whole of Vimy Ridge, except its northern end, the conquest of which was completed next day. Five villages fell into British hands and 6000 prisoners. Subsequent days saw the extension of the victory, but though Vimy village, Givenchy-en-Gohelle, and other important points were taken, the fortified villages of Héninel and Wancourt held out by dint of machine-guns, and prevented the possibility of the Third Army's joining hands with the Fifth Army beyond the third line of the German defences until it was too late. The whole of the expected gains were therefore not realized, but the possession of the Vimy Ridge was invaluable, and became a most important factor in stemming Ludendorff's rush in 1918, when he attacked the Third Army after destroying the Fifth.
The British attacks did not end on 11th April, as they should have done, but were continued here, as well as at other portions of the British line to its junction with the French armies, in order to lend assistance to Nivelle while his attack in Champagne was in progress. It was a very costly procedure, and its scope may be inferred from the statement that on 23rd April a "second phase of the battle of Arras" began; another 12-mile front east of Arras was launched on 3rd May; and there were bloody encounters about Bullecourt or Fontaine-les-Croiselles on 7th and 12th, 15th and 16th, and 21st May. Some 20,000 German prisoners were captured in these preliminary spring operations, but the drainage in casualties to the British armies was heavy, and more damaging still was the loss of time by the postponement of Field-Marshal Haig's major plan farther north.
This, however, was at last begun on 7th June by the assault on the Messines-Wytschaete Ridge, which, under the name of the 'Battle of Messines' denotes one of the most completely successful actions fought in that year. It was undertaken by the Second Army (General Plumer), and the preparation for it, including the mining of the ridge, had been as near perfection as possible. The attack was launched; the mines which blew the German front line to pieces were exploded on the morning of 7th June at ten minutes past three. Nine miles of front were stormed and 6400 prisoners taken. In the next week the number of prisoners was considerably augmented; German counter-attacks were beaten off; and the captured position enlarged and firmly consolidated.
From this time forward the operations of the
British armies may be envisaged as an attempt to enlarge the great bulge of the Ypres salient by fighting their way up to and along the ridges which enclosed it, so as to force the Germans to relinquish their hold on the coast near Nieuport, Zeebrugge, and Ostend. One very awkward spoke was put in the British wheel by an attack (10th July) on the extreme coastal sector of Lombaertzyde and the mouth of the Yser, by which any combined sea and land attack that might have been projected by the British was discounted. Most of the positions were recovered, but the amphibious plan had perforce to be postponed.
The putting into effect of Sir Douglas Haig's major plan, after the preliminary step of the capture of the Messines Ridge had been taken, did not operate till 31st July, when the 'Third Battle of Ypres' began, with a combined British and French attack on a 15-mile front beyond Boesinghe, on the Yser-Ypres Canal, to Zillebeke. The attack was conducted by the First French Army (General Anthoine); the bulk of the fighting fell on the Fifth British Army (General Gough). Twelve villages were taken and 5000 prisoners. There was, and could be, no break-through. The Germans rallied to a counter-attack, and were able to do so because their defences, their concrete pill-boxes, and their machine-gun effectiveness could, and did, hold up attacks before they progressed too far.
The rest of the British campaign in 1917 till it was arrested by the torrential rains of a wet October, and by the mud of the impossible declivities, may be summed up as a series of desperate forward thrusts which exacted each its toll of prisoners, ground, and positions, but none of which succeeded in its object of inflicting a lethal injury on the German resistance. In the end these attacks had to cease while the last fragment of coveted ridge, the Passchendaele spur, was still not won, because on that ridge, as elsewhere, though blood had been poured out like water, and losses endured with unflinching fortitude, flesh and blood could do no more. The chief actions were as follows:
15th Aug.—British attack on wide front from north-west of Lens to Bois Hugo, north-east of Loos. Enemy's position penetrated to 1 mile depth.
16th Aug.—Franco-British attack on 9-mile front north of Ypres-Menin road. British carry Langemarck.
15th to 21st Sept.—Second phase of third battle of Ypres. 3000 Germans captured.
4th Oct.—British advance on 8-mile front, anticipating German attack east of Ypres. 3000 German prisoners.
9th Oct.—Third phase of third battle of Ypres. One mile advance on Passchendaele Ridge. 2000 prisoners.
6th Nov.—British attack on Ypres Ridges. Canadians capture Passchendaele.
These attacks were interspersed with costly minor encounters, and by the repulse or endurance of counter-attacks. The battle may be said to have closed by stress of weather in mid-November.