The Gheluvelt Plateau actions, July–August 1917 took place from 31 July to 27 August, during the Third Battle of Ypres (31 July – 10 November 1917) in Belgium, in the First World War. The British Fifth Army and the German 4th Army fought for possession of the plateau at the highest part of the ridges to the south-east, east and north-east of Ypres in West Flanders. The 4th Army had been building defensive positions in the Ypres Salient since 1915 and the Gheluvelt Plateau was the most fortified section of the front. The Fifth Army had made the plateau its main objective during the Battle of Pilckem Ridge (31 July – 2 August) but the II Corps advance was contained short of its objectives and German counter-attacks later recaptured some ground.
The ground had been churned by artillery-fire and beginning late on 31 July, torrential rains lasted until 5 August, turning the ground into a sea of mud and flooded shell craters. An attack by II Corps on 2 August, postponed to 10 August, led to the Capture of Westhoek but Inverness Copse, Glencorse Wood and Nonne Bosschen were re-captured by German counter-attacks. The German defensive success was costly even with new tactics and began to concern German commanders. In a dry spell, the Fifth Army attacked again at the Battle of Langemarck but II Corps was again repulsed by counter-attacks of the German ground-holding divisions and their supporting (specialist counter-attack) divisions. The Royal Flying Corps flew more battlefield reconnaissance and ground attack sorties but a German hasty counter-attack () overran a brigade of the 56th (1/1st London) Division, leaving British troops further north outflanked, forcing them to retreat.
On 22 August, the 14th (Light) Division captured Inverness Copse and then lost it to a German methodical counter-attack () on 24 August. A tank–infantry attack failed on 27 August, when the tanks bogged down and another attempt was cancelled on 31 August. The sodden ground hampered all movement, made tank operations almost impossible and smothered shell explosions. Low cloud and fog obstructed communication between the front line and rear, impeding liaison between British artillery and their observation aircraft. Despite considerable tactical refinements by the British, the German defenders, who had to endure the same exhausting and morale-sapping conditions, held on at Inverness Copse and Glencorse Wood. British morale fell so low that some men were taken prisoner without a fight; the Germans found them bitter over their failures but the success of the 4th Army was costly in casualties.
After 24 August, Field Marshal Sir Douglas Haig, the British Expeditionary Force (BEF) commander, moved the Fifth Army–Second Army boundary again, this time northwards to the Ypres–Roulers railway and relieved II Corps with the I Anzac Corps and X Corps. After a three-week lull to improve communications, during which the rains stopped and the ground dried, the British captured much of the Plateau on 20 September, during the Battle of the Menin Road Ridge (20–26 September). In 1929, John Charteris, the BEF head of intelligence from 1915 to 1918, wrote contradictory remarks about the August climate in Flanders, which influenced later writers. The official historian, James Edmonds rebutted Charteris in 1948 and also criticised Gough, despite including much contrary evidence. In 1996, Prior and Wilson wrote that Gough had planned attritional "bite and hold" operations, rather than attempts to break through the German defences, contrary to claims by many other writers, including the official historian.
Background
Topography
Ypres is overlooked from the south-west by Kemmelberg (Kemmel Hill) and from the east by low hills running south-west to north-east, with Wytschaete (Wijtschate) and Hill 60 to the south of Verbrandenmolen (), Hooge, Polygon Wood and Passchendaele (Passendale). Wytschaete is from Ypres, at Hollebeke the ridge is distant and recedes to distant at Polygon Wood. Wytschaete is the highest point, about above the plain; on the Ypres–Menin road at Hooge, the elevation is about and is at Passchendaele. The rises are slight, apart from the vicinity of Zonnebeke, which has a gradient of From Hooge and to the east, the slope is near Hollebeke, it is height variations are subtle and resemble a saucer lip around the city. The main ridge has spurs sloping east and the spur at Wytschaete runs south-east to Messines, with a gentle slope to the east and a to the west. Further south is the muddy valley of the Douve river, Ploegsteert Wood (Plugstreet to the British) and Hill 63. West of Messines Ridge is the parallel Wulverghem (Spanbroekmolen) Spur, with the Oosttaverne Spur, also parallel, further to the east. The general aspect south and east of Ypres is one of low ridges and dips, gradually flattening northwards beyond Passchendaele into a featureless plain.
Possession of the higher ground to the south and east of Ypres gave the Germans easy observation, plenty of opportunities for enfilade fire and converging artillery bombardments. The 4th Army could also move artillery, reinforcements, supplies and stores in dead ground. The ridge had woods from Wytschaete to Zonnebeke giving good cover, some being of notable size like Polygon Wood and those named Battle Wood, Shrewsbury Forest and Sanctuary Wood by the British. In 1914, the woods contained undergrowth but by 1917, artillery bombardments had reduced the woods to a wilderness of tree stumps, shattered tree trunks and barbed wire lying tangled on the ground amid shell-holes; fields between the woods were wide and devoid of cover. Roads in this area were unpaved, except for the main ones from Ypres, with occasional villages and houses along them. In 1914, the lowland west of the ridge had been a mixture of meadow and fields, with high hedgerows dotted with trees, cut by streams and ditches emptying into canals. The main road to Ypres from Poperinghe to Vlamertinge is in a defile, easily observed from the ridge.
Strategic developments
Only two US divisions had arrived in France by late August but the mutinies in the French armies after the Nivelle Offensive had abated. The Second Battle of Verdun, in support of the offensive in Flanders, had been delayed from mid-July, which forfeited strategic surprise. German artillery frequently bombarded French positions with the new mustard gas and several spoiling attacks disrupted French preparations. On 20 August, the French attacked on an front and recaptured Mort Homme and Hill 304, taking for the loss of them killed or missing. The 5th Army was not able to deliver large counter-attacks, because its divisions () had been transferred to Flanders; local operations continued into November. On the Eastern Front, the Kerensky Offensive had been defeated by the Central Powers; the Russian armies began to disintegrate and Germany and Austria-Hungary were able to reinforce other fronts. In the south, the Italian army began the Eleventh Battle of the Isonzo on 17 August and captured the Bainsizza Plateau, leading the Austro-Hungarians to appeal for German help; a French offensive in Greece on the Salonika front was repulsed.
Tactical developments
Battle of Messines
Field Marshal Sir Douglas Haig, commander of the British Expeditionary Force intended to exploit success in the Second Army (General Herbert Plumer) attack on the Messines–Wytschaete Ridge on 7 June, by gaining a foothold on the Gheluvelt Plateau as a preliminary to the main offensive out of the Ypres Salient. Plumer planned for II Corps (Lieutenant-General Claud Jacob) and VIII Corps (Lieutenant-General Aylmer Hunter-Weston) to attack either side of Bellewaarde Lake, to capture the higher ground for west of a line from Stirling Castle northwards to Westhoek (West Corner). Plumer wanted three days to transfer guns and howitzers northwards from Messines Ridge. On 6 June, the day before the Messines attack, the Fifth Army commander, General Hubert Gough, had told Haig that he preferred to wait until the Northern Operation, the main offensive out of the Ypres Salient or to have command of the II and VIII corps attack. On 8 June, both corps sent patrols forward which reported determined resistance, prompting Haig to ask Plumer to begin the attack at once. Plumer wanted to wait for the artillery to arrive and Haig transferred command of the II and VIII corps to the Fifth Army.
Haig ordered Gough to conduct a limited attack with the two corps but Gough reported that a success would put the British in a "very exposed and difficult salient" and that it would be better to conduct the attack with the main offensive. (Field Marshal) Rupprecht, Crown Prince of Bavaria, the commander of Army Group Rupprecht of Bavaria () on the northern part of the Western Front, thought that the British success on 7 June foreshadowed an attack against the 4th Army to capture the higher ground between Gheluvelt and Zandvoorde in the north and Comines on the Lys (Leie) river, south of Messines Ridge. Rupprecht contemplated a retirement to a line from Werviq to Zandvoorde and Hooge as soon as the British attacked, then to retreat to the , which had been built earlier in 1917. In late June, Rupprecht expected the British to conduct battering-ram attacks on narrow fronts, with overwhelming artillery-fire, to drive wedges into the defences of the 4th Army and deplete German reserves, preparatory to an advance out of the Ypres Salient on a broad front ( "breakthrough attack launched on a broad basis").
Peripheral operations
Between the end of the Battle of Messines and the Battle of Pilckem Ridge at Ypres beginning on 31 July, operations against Lens and Lille were to be made by the First Army in late June. Offensive operations were planned near Gavrelle and Oppy, along the Souchez River against a German salient between Avion and the west end of Lens, the capture of Reservoir Hill (Hill 65) south of Lens and an attack by the Canadian Corps on Hill 70, at the northern outskirts of Lens. The attacks were conducted earlier than intended, to use heavy and siege artillery before it was transferred to Ypres; the Souchez operation was cut back and the attack on Hill 70 postponed. the Battle of Hill 70, south of Ypres, took place from 15 to 25 August. Three of the Canadian divisions captured the hill, inflicted many casualties on five divisions of the German 6th Army and pinned down troops reserved for the relief of tired divisions on the Flanders front. (Lieutenant-General) Hermann von Kuhl, the chief of staff of , wrote later that it was a costly defeat and wrecked the plan for relieving fought-out (exhausted) divisions from Flanders.
Prelude
German preparations
Fortifications
The 4th Army (General Friedrich Sixt von Armin) was responsible for defence of the Western Front from Lille to the North Sea, which included the Ypres Salient. In early 1917, German corps had been renamed based on a corps headquarters, with fresh divisions coming under command as tired ones were withdrawn, rather than the traditional permanent establishment of divisions. The IX Reserve Corps became and held of the front south of the Menin road northwards, with three ground holding divisions () in the front line and three (specialist counter-attack) divisions in reserve. The III Bavarian Corps was renamed and held of front from the Menin road north to the Gheluvelt Plateau and Pilckem, with three and two divisions. The divisions were kept out of sight behind the Menin and Passchendaele ridges. About further back were four more divisions and beyond were another two divisions in army group reserve.