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 and restore a war of movement.

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.

At the Frévent Conference on 27 July, Field Marshal French failed to persuade Ferdinand Foch that an attack further north offered greater prospects for success.

At a conference on 6 September, Haig announced to his subordinates that extensive use of chlorine gas might facilitate an advance on a line towards Douai and Valenciennes, despite the terrain, as long as the French and British were able to keep the attack secret.

[2] 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.

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.

[5] The British commanders did not grasp that German defensive tactics included placing the second line of machine gun nests on the reverse slopes of hills; destroying them would need howitzers and high explosive shells.

Wanting to be closer to the battle, French had moved to a forward command post at Lilliers, less than 20 mi (32 km) behind the First Army front.

He left most of his staff behind at GHQ and had no direct telephone to the army HQ, which attacked at 6:30 a.m. on 25 September, sending an officer by car to request the release of the reserves at 7:00 a.m.[8] In many places British artillery had failed to cut the German wire.

[23] Rawlinson wrote to the King's adviser Arthur Bigge (28 September) From what I can ascertain, some of the divisions did actually reach the enemy's trenches, for their bodies can now be seen on the barbed wire.Major-General Richard Hilton, at that time a Forward Observation Officer, said of the battle, A great deal of nonsense has been written about Loos.

The only two things that prevented our advancing into the suburbs of Lens were, firstly, the exhaustion of the "Jocks" themselves (for they had undergone a bellyfull [sic] of marching and fighting that day) and, secondly, the flanking fire of numerous German machine-guns, which swept that bare hill from some factory buildings in Cite St. Auguste to the south of us.

But, alas, neither ammunition nor reinforcements were immediately available, and the great opportunity passed.French had been criticised before the battle and lost his remaining support in the government and army due to the British failure and a belief that he handled poorly the reserve divisions.

[28] James Edmonds, the British official historian, gave German losses in the period 21 September – 10 October as c. 26,000 of c. 141,000 casualties on the Western Front during the autumn offensives in Artois and Champagne.

[35] Haig thought it might be possible to launch another attack on 7 November but the combination of heavy rain and accurate German shelling during the second half of October persuaded him to abandon the attempt.