 The Flanders campaign was postponed , because of the German offensive at Verdun and the demands of the Battle of the Somme . When it became apparent that the Nivelle Offensive ( 16 April – 9 May 1917 ) had failed to achieve its most ambitious objectives , Haig instructed the Second Army to capture the Messines – Wytschaete Ridge as soon as possible . Haig intended to force the Germans to move troops away from the French armies on the Aisne front , where demoralisation amid the failure of the Nivelle Offensive had led to a number of mutinies . British operations in Flanders would relieve pressure on the French Army , as the Battle of the Somme had done . The capture of Messines Ridge would give the British control of the strategically important ground on the southern flank of the Ypres Salient , shorten the front , deprive the Germans of observation over British positions further north and would occupy ground from which the British could observe the southern slope of Menin Ridge at the west end of the Gheluvelt plateau , in preparation for a larger offensive in the Ypres Salient . 
