A thick mist which hung over the position for several days before the attack assisted the preparations incalculably, as it prevented the enemy’s aeroplanes from obtaining any information. On the 17th and 18th of November the 61st and 60th Brigades, which were to deliver the assault on the Divisional front, were relieved by troops of the 12th and 6th Divisions; outposts belonging to the 20th Division were left, however, covering the original front. On the 19th the 61st on the right and the 60th on the left took over the new Divisional line, which then extended only from a thousand yards north-west of Gonnelieu to the north-east of Villers Plouich. At the same time the 59th Brigade, to which a special rôle had been assigned, moved back to Gouzeaucourt in reserve. The concentration was a very complicated and difficult one, especially for the 20th Division, which was manning the trenches up to the last moment. Concentration camps for the 20th and for three other divisions had been made and completely camouflaged by the 83rd, 84th and 96th Field Companies R.E. and the 11th D.L.I. under the orders of Lieut.-Colonel Newell, the C.R.E. The essence of the plan was to surprise the enemy, overwhelm him with a sudden rush of tanks followed by infantry, and break his line before he had time to realise the nature or the locality of the attack. There was therefore no preliminary bombardment, nor even was any registration of the guns allowed. The infantry lines were to be preceded by waves of tanks and the attack covered by standing barrages, which were to lift from objective to objective as the assaulting troops advanced. Of the 60 tanks at the disposal of the Division 36 were allotted to the 61st Brigade and 24 to the 60th. The general direction of the attack was north-east, across the Hindenburg and Hindenburg Support Lines on the front of La Vacquerie and Welsh Ridge. The left boundary was the Villers Plouich--Marcoing railway; the right boundary an approximately parallel line about 2500 yards to the south-east. The first objective followed the general line of a track from Banteux to Ribécourt, between the road from La Vacquerie to Bonavis and the railway. La Vacquerie, a particularly strong point, was the key position of the enemy’s first line of defence on the right. This village and the trenches north-west of it formed an initial objective in the area of the 61st Brigade. The second and final objective included the whole of Welsh Ridge, from a point in the sunken road nearly 3000 yards north-east of La Vacquerie to the railway 1200 yards south-west of the railway junction at Marcoing. The 12th Division on the right and the 6th Division on the left were to attack objectives prolonging those of the 61st and 60th Brigades.