In mid-1917 the Germans held the high ground of the Messines Ridge in Flanders. It overlooked British positions in the Ypres Salient, meaning preparations for any British attack in this area could easily be seen and shelled. In mid-1917 the British intended to launch just such an attack, so for this reason they first needed to capture the ridge.
The Salient was a vital ground for the British and Belgians, as it was some of the last Belgian territory not occupied by Germany. It was however highly vulnerable, as it was surrounded on three sides by German positions, many on high ground such as Messines. This allowed the Germans to easily observe preparations for any British attack, and more easily position artillery and reinforcements to defeat them.
For these reasons capturing the Ridge was a longstanding aim of British commanders in the area.
The attack was carefully planned and prepared for. It relied heavily on deep mines dug under the German lines. These had been begun as far back as January 1916 and there were eventually 19, filled with a total of over 450 tonnes of explosive.
The attack was set for the 7th June. For ten days beforehand a sophisticated artillery bombardment, drawing on lessons learned from the Battle of Arras in April, had cut German barbed wire and suppressed their infantry and artillery.
At 3:10am on the 7th the mines were detonated. The explosions were so loud they were heard in London. Within minutes the infantry began to advance, supported by a creeping barrage, gas and tanks. The explosions had killed an estimated 10,000 German soldiers and disorientated many of the survivors.
For the British, the attack was spectacularly successful, and most objectives were taken within 3 hours. The Germans launched counter attacks soon afterwards but without success, and by the 14th the British had captured the entire ridge.
Tanks at Messines
Messines was also the debut of the Mark IV tank. A total of 72 were used, 36 each from A and B Battalions. As usual, small numbers were assigned to individual Divisions to support the infantry.
Attacking uphill over badly cratered ground hardly played to the tank’s strengths, and the British plan treated them as accessories and didn’t rely on them. In the end 48 ended up ditched or bogged. According to Tank Corps records only 19 were able to provide any support to the infantry, but in many cases this support proved invaluable.
The main innovation for the Tanks at Messines was the Supply Tank. Conversions of obsolete Mark Is, each of these could carry forwards five ‘fills’ (a fill was one day’s worth of petrol, oil, ammunition, grease and water for one tank). Supply Tanks could cross ground wheeled vehicles couldn’t and carry far more than human porters. They also allowed fighting tanks to replenish without needing to leave the battlefield. Twelve were used at Messines.
The Battle of Messines was remarkably successful with, unusually for the First World War, the attackers taking fewer casualties than the defenders (24,562 British as opposed to 26,087 Germans). Such success, however, did lead to a level of overconfidence in the British High Command as they prepared for the Third Battle of Ypres. This battle began 6 weeks later, but under very different conditions and with very different results.