The Battle of Loos took place from 25 September to 8 October 1915 in France on the Western Front, during the First World War. It was the biggest British attack of 1915, the first time that the British used gas as a weapon and the first mass engagement of New Army divisions. The French and British tried to break through the German defences in Artois in the north and Champagne at the south end of the Noyon Salient, to restore a war of movement.
Despite improved methods, more ammunition, better equipment and gas, the Franco–British attacks were contained by the Germans, except for local losses of ground. The British gas attack failed sufficiently to neutralise the defenders and the artillery bombardment was too short to destroy barbed wire and machine-gun nests. German defensive fortifications and tactics could not be overcome by the British who were still assembling a mass army suitable for Western Front conditions.
Background
After the First Battle of the Marne frustrated Germany's bold bid for victory in the West and France's efforts failed to take the war to the Germans in Alsace-Lorraine, stalemate ensued. During the first half of 1915 French and British efforts to break through the German defences had been costly failures. In December 1914 the professional head of the German army, Erich von Falkenhayn, had been obliged to withdraw some 14 divisions from the Western Front to reinforce the Eastern Front. The French commander, General Joseph Joffre, saw an opportunity to break through the German field fortifications. The British part would be an attack at the village of Loos.
Field Marshal Sir John French and Douglas Haig (GOC First Army), regarded the ground south of La Bassée Canal, which was overlooked by German-held slagheaps and colliery towers, as unsuitable for an attack, particularly given the discovery in July that the Germans were building a second defensive position behind the front position. At the Frévent Conference on 27 July, French failed to persuade Ferdinand Foch that an attack further north offered greater prospects for success. The debate continued into August, with Joffre siding with Foch and the British commanders being over-ruled by Herbert Kitchener, the British Secretary of State for War, on 21 August.
Gas
There had been early ideas of how to use gas in the war. The British Government rejected this as it would contravene the spirit and the letters of the Hague Conventions of 1899 and 1907. If not technically outlawed, gas was felt to be unsporting. When the Germans at the Second Battle of Ypres on 22 April 1915 used gas for the first time in the war, the British had changed their minds. The decision to use gas as an offensive weapon was made on 3 May 1915, following instructions from French. G.H.Q. established a laboratory at Helfaut, near St Omer, with Special Companies of the Royal Engineers under Major Foulkes.
On 22 August, a demonstration of a chlorine wave was given at Helfaut, attracting General Haig and his corps and divisional commanders. The chlorine gas was contained in steel cylinders placed below the firing step of the front parapet of the fire trench. A flexible copper pipe connected the cylinder with an ordinary half-inch iron pipe, which was placed on the top of the parapet pointing towards the German trenches and weighted with sandbags. The cylinders functioned on the principle of a soda-water syphon, on opening the cock, the gas came out as a yellowish-white vapour, then a greenish-yellow cloud a few feet from the pipe. It was hoped that, given the greater density of the gas, it would descend into subterranean shelters such as the deep dug-outs of the German trenches and the cellars in the villages, where artillery fire could not penetrate.
The Germans would be forced into the open, unable to maintain stubborn resistance. In the event of the infantry assault being executed in immediate succession to the gas discharge, the probability of success would be significantly increased. The demonstration showed the importance of chlorine gas in offensive operations. General Haig was ordered to cooperate with General Joffre's plans and the gas demonstration led to the idea of using it on the attack front south of La Bassée canal.
Prelude
British preparations
The battle was the third time that specialist Royal Engineer tunnelling companies were used to dig under no-man's-land, to plant mines under the parapets of the German front line trenches, ready to be detonated at zero hour.
Order of battle
The forces deployed for the offensive consisted of two corps. I Corps (Lieutenant-General Hubert Gough) comprising the 2nd Division (Major-General Henry Horne), the 7th Division (Major-General Thompson Capper), the 9th (Scottish) Division (Major-General George Thesiger) and the 28th Division (Major-General Edward Bulfin). IV Corps (Lieutenant-General Sir Henry Rawlinson) comprised the 3rd Cavalry Division (Major-General Charles Briggs), the 1st Division (Major-General Arthur Holland), the 15th (Scottish) Division (Major-General Frederick McCracken) and the 47th (2nd London) Division TF (Major-General Charles Barter).
French decided to keep a reserve consisting of the Cavalry Corps, the Indian Cavalry Corps and XI Corps (Lieutenant-General Richard Haking), which consisted of the Guards Division and the New Army 21st Division (Major-General George Forestier-Walker) and 24th Division (Major-General John Capper) recently arrived in France and a corps staff (some of whom had never worked together or served on a staff before). Archibald Murray, the Deputy Chief of the Imperial General Staff (DCIGS) advised French that as recently trained troops, they were suited for the long marches of an exploitation rather than for trench warfare. French was doubtful that a breakthrough would be achieved. Haig and Foch, commander of the groupe des armées du nord (Northern Army Group), wanted the reserves closer, to exploit a breakthrough on the first day. French agreed to move the reserves nearer to the front but still thought they should not be committed until the second day.
The defence consisted of IV Corps (General Six von Armin) comprising the 117th Division (General Ernst Kuntze) the 8th Division (Major-General Thilo von Hanstein) the 7th Division (Lieutenant-General Johannes Riedel) and the 123rd (Saxson) Division (Major-General Karl Lucius). VII Corps (General Hermann von François) comprised the 14th Division (Major-General Constantin von Altrock). II Bavarian Corps (Lieutenant-General Otto von Stetten) comprising the 9th 17th and 18th Bavarian Infantry Divisions, the Guard Corps comprising the 1st Guard Division (Major-General Prince Eitel Friedrich of Prussia) and the 2nd Guard Division (Lieutenant-General Maximilian von Höhn). Additionally, there were the X Reserve Corps (General Robert Kosch) comprising the 2nd Guard Reserve Division (Lieutenant-General Paul Weese).
British plan
The IV Corps (Rawlinson) on the right of the First Army had as its first task the capture of the German frontline defences along the Grenay frontal arc between the Double Crassier (slagheap) and the Vermelles−Hulluch road. The British advance was to be continued by the 15th (Scottish) Division and the 1st Division. On the right, the 47th (1/2nd London) Division, was to stop along the Loos valley between the Double Crassier and the Loos Crassier (both included) and form a defensive flank, including the "chalk pit", opposite Lens. The 15th (Scottish) Division and 1st Division were to advance over Hill 70 and the Lens road through the second German position between St Auguste and Hulluch to the line of the Haute Deule canal. The right of the 15th (Scottish) Division was to meet the French Tenth Army advancing south of Lens on the Lens−Carvin road, a few miles east of St Auguste; the Lens–Henin–Lietard road was made the boundary between the French and British. Rawlinson was under the impression that French expected a breakthrough and would have his reserves nearby to exploit it.
The IV Corps attack was to be pushed to the utmost extent, with no corps reserve. The artillery of IV Corps was to support the advance and adapt to it as soon as possible. The artillery of the 47th (1/2nd London) Division, reinforced by 1 Group Honourable Artillery Regiment was to advance and form a pivot on the right around Mazingarbe (1.5 mi (2.4 km) north-northwest of Grenay) and Les Brebis (0.99 mi (1.6 km) northwest of Grenay), facing Lens, ready to eliminate the German batteries at Lens. The artillery of the 15th (Scottish) Division was to advance to positions close behind the original British front-line trenches and form a strong centre between North Maroc and Fosse 7 near the Bethune–Lens road, where the batteries would be covered by the crest of the Grenay spur. The artillery of the 1st Division was to advance via Le Rutoire (south-east of Vermelles) and take up a position 0.99 mi (1.6 km) north of Loos near the Vermelles–Hulluch road behind the British front line.
I Corps (Gough) was to break through the German first defensive system between the Vermelles–Hulluch road and the La Bassée canal with its 7th Division, 9th (Scottish) Division and the 2nd Division. The plan was to advance eastward across the plain to the German second defensive line, located a mile beyond and to continue without pause toward the Haute Deule canal. This strategy aimed to capitalise on the element of surprise and prevent the German reserves from reinforcing their rear defences. The 7th Division and 9th (Scottish) Division were to breach the German second line along the Hulluch–Haisnes front and proceed towards Wingles and Douvrin, respectively. The 7th Division's right flank was to move along the Vermelles–Hulluch–Pont-à-Vendin road, maintaining contact with IV Corps. The 2nd Division, on the left, was assigned to capture Auchy village and secure the railway running north-west from Haisnes to the canal, forming a defensive flank to support the further advance of the 7th Division and the 9th (Scottish) Division. To bolster the left flank, east of Haisnes, the 9th (Scottish) Division was instructed to deploy a small mobile flank guard. No corps reserve was allocated, as it was expected that XI Corps with the 21st Division and the 24th Division would arrive promptly.
An alternative plan was devised in case the 2nd Division failed to break through. It was acknowledged that capturing Auchy posed significant challenges, given the limited bombardment and the reliance on favourable wind conditions to carry gas into the village cellars and dugouts. If the assault on Auchy did not succeed, the 2nd Division was to hold its position, while the 9th (Scottish) Division created the defensive flank by occupying a line from the northern edge of Fosse 8, following a German communication trench known as Pekin Alley, extending eastward to Haisnes. Under this contingency, the 7th Division alone would continue the advance to the Haute Deule canal. As with the IV Corps front, the German force immediately available to counter I Corps was limited, consisting of Reserve Infantry Regiment 11, Infantry Regiment 16 and Infantry Regiment 56.
Battle
25 September
In many places British artillery had failed to cut the German wire. The engineers manning the chlorine gas cylinders warned against their use, because of the weakness and unpredictability of the wind but they were overruled by Gough. In some places the gas drifted back into the British lines and caused more British than German casualties.
IV Corps
At 6.30 a.m., forty minutes after the gas attack began, the 140th and 141st Brigades of the 47th (1/2nd London) Division began their advance. The gas had spread best in this sector, possibly due to the slope of the terrain towards the Loos valley. The advance was also obscured by a thick cloud of smoke from two batteries of Stokes mortars. As soon as the gas reached the German positions, they opened fire, which subsided shortly afterwards. Within a few minutes, both brigades penetrated the front trench behind the smoke and gas curtain; shortly afterwards the resistance collapsed. By 7:30 a.m., the 7th and 6th Battalions (City of London Regiment) had reached the 140th Brigade objective, the German support trench from the centre of the spoil heaps to the Bethune–Lens road. There was a German counter-attack on the right flank of the 7th Battalion but it was repulsed.