(iii) Twelve tanks to operate with the Fifth Army.
The Third Army plan of operations was as follows: The VIth and VIIth Corps were to attack south of the river Scarpe between Arras and Mercatel. Their objective ran from a point 2,000 yards south-east of Henin-sur-Cojeul northwards to Guemappe, thence east of Monchy-le-Preux to the Scarpe. This objective was 10,000 yards in length and 8,000 in depth. It contained two formidable lines of defences:
(i) The Cojeul-Neuville Vitasse-Telegraph hill-Harp-Tilloy les Mafflaines line, much of which had been fortified for over two years.
(ii) The Feuchy Chapel-Feuchy line.
South of these systems was the Hindenburg Line, and east of them Monchy-le-Preux, which dominates the whole of the surrounding country. Three valleys lie between this eminence and the city of Arras.
The XVIIth Corps was to continue the attack north of the river Scarpe and occupy a line running from east of Fampoux to the Point du Jour, and thence to a point 4,000 yards east of Roclincourt. The country along the northern bank of the Scarpe was intricate, and in it many excellent positions existed for hostile machine-guns. Further, the railway running to Bailleul was in itself a formidable obstacle.
The First Army attack comprised the taking of the famous Vimy Heights, Thelus and the hill north of Thelus, a position considered one of the strongest in France.
The Fifth Army was to operate between Lagnicourt and the right of the Third Army, driving northwards towards Vis-en-Artois. The operation to be carried out by this Army was a most difficult one. The destruction of the roads and the bad weather had rendered it impossible to move forward sufficient artillery—a sine qua non of all attacks of this period.
The whole of the above operations were to be considered as the preliminaries to the advance of two Cavalry Divisions and the XVIIIth Corps south of the Scarpe, which force was to break through at Monchy and advance eastwards on to the Drocourt-Queant line.
The general preparations required for a tank battle will be dealt with in another chapter, suffice it here to state that they were divided up as follows—preliminary reconnaissances, the formation of forward supply dumps, the preparation of tankodromes and places of assembly, the programme of rail movements and the fixing and preparing of the tank routes forward from the tankodromes.