Cyril Falls, the author of the British official history of the battle (and an officer in the war) wrote:"‘Easter Monday of the year 1917 must be accounted from the British point of view one of the great days of the War" The first day of the Battle of Arras was, in his view, "among the heaviest blows struck by British arms in the Western theatre of war."
At 5.30 a.m. on Easter Monday, 9 April 1917, the British and Canadian infantry ‘hopped the bags’ and advanced through a snowstorm. Fifteen minutes earlier German batteries had been bombarded with poison gas. Like artillery, machine gun tactics had increased in sophistication since the beginning of the war. Massed machine guns fired a barrage over the heads of the attacking infantry, while forty tanks rumbled into action alongside. The first day of Arras was highly successful. At Vimy Ridge, with the support of nine Heavy Artillery Groups (seven of them British) the Canadians captured most of this formidable position with little difficulty, although at the cost of 11,000 casualties.
As with everything on the Western Front, the cost in casualties was high.
The BEF’s daily loss rate of 4,076 at Arras was greater than the Somme (2,943), Passchendaele (2,323), or the Hundred Days battles of 1918 (3,645)