18 August – 6 September 1918: the Advance in Flanders. Second and Fifth Armies begin operations in the Lys valley, recapturing the ground lost in April 1918.
Second Army (Plumer)
X Corps (Stephens)
30th Division
36th (Ulster) Division.
XV Corps (de Lisle)
9th (Scottish) Division
29th Division
31st Division
40th Division.
XIX Corps (Watts)
6th Division
34th Division
41st Division
27th American Division.
Fifth Army (Birdwood)
XI Corps (Haking)
59th (2nd North Midland) Division
61st (2nd South Midland) Division
74th (Yeomanry) Division.
XIII Corps (Morland)
4th Division
19th (Western) Division
46th (North Midland) Division.
Subsequent: the action of Outtersteene Ridge, 18 August 1918
Second Army (Plumer)
XV Corps (de Lisle)
9th (Scottish) Division
29th Division
31st Division (12th Norfolk Regiment only).