Fighting began at 12.40 p.m. on Sunday the 23rd with a bombardment from between five and six hundred German guns along the whole twenty-five miles of front. It did surprisingly little damage in spite of the spotting by German aeroplanes; and when the German infantry came forward in massed formation, they discovered that their shelling had had no effect upon the moral of our troops or the accuracy of their rifle-fire. The Germans fought, of course, with obstinate courage and advanced again and again into the murderous fire of our rifles and machine guns and against occasional bayonet charges. But their own shooting went to pieces under the stress, and the frontal attack was a failure. Success there could not, however, ward off Von Buelow's threat to our right flank, and under the converging pressure Binche and then Mons itself had to be evacuated. But it was the long-delayed news of the French defeat and withdrawal on the whole of the rest of the line, coupled with more accurate information about the size of the German force, that determined the abandonment of the British position. Sir John French had to hold on till nightfall, but orders were given to prepare the way for retreat. The weary troops were to have a few hours' rest and start at daybreak. Their retreat was covered by a counter-attack soon after dawn by the First Division on the right which suggested to the Germans that we had been strongly reinforced and intended an offensive. Meanwhile Smith-Dorrien moved back five miles from the Canal, and then stood to protect the withdrawal of the First Division after its feint attack. It was a heavy task, and the 9th Lancers suffered severely in an attempt to hold up the Germans at Audregnies. But by Monday afternoon Haig's First Army Corps was back on the line between Maubeuge and Bavai, and Smith-Dorrien fell into line from Bavai westwards to Bry.
The design was to offer a second battle in this position, and entrenchments were begun. The fortress of Maubeuge and the Sambre gave some protection to the British right, but the Sambre was only of use in front if the Meuse was held by the French on the right and Von Kluck could not outflank on the left. Neither of these conditions was fulfilled: Von Kluck had seized Tournai and captured the whole of the French Territorial brigade which attempted to defend it, while the Meuse had been forced and the three French armies were in full retreat. A battle on the Maubeuge-Bry line would invite an encirclement from which the British had barely escaped at Mons, and the retreat was reluctantly continued to Le Cateau. Marching, the First Army Corps along the east of the Forest of Mormal and the Second along the west, our troops reached at nightfall on the 25th a line running from Maroilles through Landrecies and Le Cateau to Serainvilliers near Cambrai; but they had little rest. About 10 p.m., amid rain and darkness, the Germans got into Landrecies. In the fierce hand-to-hand struggle which ensued, the individual resourcefulness of our men gave them the advantage, and the Germans were driven out by detachments of the Grenadier, Coldstream, and 1st Irish Guards. They were simultaneously repulsed at Maroilles with some French assistance; but daybreak saw a third and more powerful attack delivered on Le Cateau. Sir John French had told Smith-Dorrien the night before that he was risking a second Sedan by a stand. But Smith-Dorrien thought he had no option. For eight hours on the 26th his men, reinforced by Snow's Division, but outnumbered in guns by nearly four to one, held their own, until another envelopment was threatened by Von Kluck. Fortunately the struggle had apparently exhausted the Germans; Sordet's cavalry had ridden across Smith-Dorrien's front and protected his left from envelopment; and the remnants of the three divisions were able to withdraw. The retreat was harrowing enough, and the 1st Gordons, missing their way in the dark, fell into the hands of the Germans and were all killed, wounded, or taken prisoners. But Le Cateau had taken the sting out of the German pursuit, and touch was at last regained with French forces to the east, with a newly-formed corps under D'Amade to the west, and with a Sixth French army which Maunoury was collecting on the Somme. On the evening of Friday the 28th Smith-Dorrien reached the Oise between Chauny and Noyon and Haig at La Fère. The First Army Corps had marched by Guise; the loss of a detachment of Munsters by misadventure early on the 27th was redeemed by the defeat on the 28th of two German columns by two brigades of Allenby's cavalry led by Gough and Chetwode. That night the Expeditionary Force had its first real sleep since Sunday, and next day there were no marching orders.