The major German attack on the French Army at Verdun, which started on 21 February 1916, came at a time when the British Army was considerably strengthening its ranks with the arrival of ten new divisions on the Western Front. To relieve pressure on the French, Allied command decided to replace the French 10th Army stationed in Artois with British units and began planning a major offensive in Somme.

In March 1916 British soldiers duly replaced their French counterparts along a thirty kilometre stretch of the front from Loos-en-Gohelle to Ransart, south of Arras, and the front they now had to defend extended from Ypres to the Somme. In relieving their allies, the British discovered a system of relatively shallow trenches which were badly maintained and had few fortified shelters. Many of the Commonwealth soldiers were shocked by the considerable number of shallow graves and unburied bodies lying near the trenches.

The sector of Vimy was a particular challenge for the new arrivals because not only could the Germans easily fire on British lines from the top of the ridge, they could also move easily around their rear under the cover of the ridge. From the very start the British brought in the specialist tunnellers of the Corps of Royal Engineers in an attempt to wrest the initiative from the Germans. For several months both sides engaged in an intense underground war which consisted of planting heavily-charged land mines under the front lines of the opposite camp and trying to thwart each other's tunnelling activities.

When they realized that the British were winning the war under ground the Germans decided to launch a surface offensive for the purpose of capturing the entrances to the Allies' tunnels. Early in May 1916 the Germans began to ratchet up their artillery and mortar activity from Vimy Ridge, directing their shells on the British front line and communication lines. Having observed intense Allied troop movements around Arras, in preparation for the offensive on the Somme, the Germans felt the time was ripe for their attack. On 21 May the offensive began with a powerful bombardment lasting several hours which focused on a narrow section of the front, the Germans firing deep into the Allies' lines. In relative terms, the bombardment was one of the heaviest of the Great War with 70,000 shells fired in four hours. The Germans exploded a mine and then sent in their infantry which easily took the British front line, capturing numerous British soldiers in their shelters and "turning" the trenches on their makers. A British counter-attack on 23 May was nipped in the bud by German shelling and machine gun fire. Subsequently the British command decided to leave things as they stood, preferring to concentrate its energy on the forthcoming offensive in Somme.

Yves Le Maner
Director of La Coupole
History and Remembrance Centre of Northern France

• "The actions of Spring 1916" on www.1914-1918.net