Arrangements were at once made by Brigade for a further withdrawal, and this was rendered the more imperative by the rapid advance made on the left of the Corps front during the day. In this region the enemy were already threatening Guiscard, eight miles north-west of Chauny, and the security of Noyon itself was seriously in doubt.
For several hours Grover's details and the tiny Condren force maintained their fight, but in the afternoon the withdrawal began in accordance with the orders already issued. Under Grover's command the mixed force was skilfully withdrawn, fighting a stubborn rearguard action, to a prepared position about 1000 yards east of Abbécourt, while the detached portion of the 2/4th Londons on Grover's left, now about 60 strong, fell back to Ognes, and marched into Besme across the Oise about midnight. Early in the afternoon Major Grover was wounded and Capt. Askham took over his command. By 4.30 p.m. the Abbécourt position, being no longer tenable, was vacated and the whole of the 173rd Group, including 2/4th and 8th Londons, 503rd Field Company, R.E. and the 6th Dismounted Cavalry Brigade, had crossed the Oise at Manicamp. About the same time the Condren garrison which had held manfully to its positions since the opening of the battle got clear across the river.
Before this withdrawal was completed the whole of the Oise bridges, and also the R.E. Dump at Chauny, were demolished, and it may be remarked that during the four days of fighting not a single gun had been lost except those destroyed by enemy shell fire.
With the withdrawal across the Oise the hardest of the Battalion's fighting in this great battle was finished, though it remained in contact with the enemy with very little rest. The Division now held a river front of over nine miles on the south bank of the Oise from Quierzy to Servais, in addition to the original four miles held by the 174th Brigade in the Forêt de St Gobain. With this enormous front in contact with an enterprising enemy no rest was yet to be expected. The early hours of the 25th March were devoted to sorting out the hopeless tangle of units which the battle had caused, and at 11.30 a.m. Lieut.-Col. Dann became responsible (in conjunction with the 6th Dismounted Cavalry Brigade) for the defence of the river crossings at Quierzy, with a composite force comprising details of four battalions, reorganised in companies as follows:
| 1 | Coy. | representing | 2/2nd Londons guarding Quierzy bridge. |
| 1 | " | " | 8th Londons on its left. |
| 1 | " | " | 2/4th Londons in support. |
This company of the 2/4th Londons was the party of 60 which had reached Besme the previous evening, and was now under 2/Lieut. Griffiths.
The same night (25th/26th March) this composite force was relieved by the 246th French Regiment and withdrew to Besme to refit, Lieut.-Col. Dann taking charge of another composite force of troops of the 175th Brigade. In the meantime the remainder of the 2/4th Londons, which had formed part of Grover's Force and were now under Askham, took up a defensive position under orders of Lieut.-Col. Chart, 18th Entrenching Battalion, east of Manicamp, on the south side of the Canal and the Ailette River. At night this party was also relieved by Lieut.-Col. Dann's force and joined the remainder of the Battalion at Besme.
The 173rd Brigade was now entirely extricated from the line, and a day of reorganisation and collection of scattered details from the various composite forces, which the needs of the moment had created, was of urgent necessity. This respite was obtained on the 26th March when the three original units were reorganised as one battalion, known as the Fusilier Battalion as follows:
| No. 1 Coy.—117 | other | ranks | 2/4th | Londons | under | Capt. Askham. |
| No. 2 Coy.— 88 | other | ranks | 2/4th | " | " | 2/Lieut. Blair. |
| No. 3 Coy.—179 | " | " | 2/2nd | " | " | Capt. Wright. |
| No. 4 Coy.—189 | " | " | 3rd | " | " | 2/Lieut. Curtis. |