The Battle of Messines on 7 June 1917 was the first action for the 2nd Tank Brigade which consisted of A and B Battalions of the Heavy Branch, each equipped with thirty-six of the new Mark IV Tanks. They would operate across the Second Army on a frontage of some 13 kms. The Second Army’s objectives were the Messines-Wytschaete ridge and the Oosttaverne line which lay beyond the ridge. 2nd Army achieved this, and the capture of 7,300 prisoners, “with comparative ease” to quote a contemporary report. The artillery preparation was so heavy and complete that ditching in shell holes in the early stages of the attack was almost a greater danger to the Tanks than anything the enemy did to them.
In A Bn’s area, owing to the extraordinary sticky nature of the ground, several of the Tanks got ditched but rapidly overcame their difficulty and followed up the attack at full speed. When the Tanks reached the top of the ridge they saw the enemy in full retreat and followed them up as fast as possible. Orders were received by No. 1 Company which was standing in support at 8 a.m. to move forward to a line on the other side of the village of Wyteschaete. All the Tanks reached the Hospice and stopped to refill at noon. They then received orders to proceed to a line on the East side of the village of Oosttaverne. Six Tanks reached the line East of Oosttaverne and four of these were ditched but remained in the forward position. The following morning the enemy counter attacked but the Tanks that had remained repelled this attack, until the arrival of supports. The mainstay of this resistance were Lieuts. Liles, Duncan and Keogh. The outcome of the battle was one of the most successful that was ever fought the captures amounting to 7,000 prisoners and 80 guns.
B Bn report on the battle is as follows. No. 4 Company’s tanks, which were working with the New Zealand Division, moved forward at dawn to attack Messines. The ground East of the Messines-Wytschaete road is practically flat but on the West side of it, from which the attack was made, it descends sharply into the valley made by the Steenbeek stream. The continuous shell fire had destroyed the river bed in places and had forced the stream to spread until it was at some points an impassable morass. No. 6 Company was split up, one Section working with the 25th Division; one with the 36th Division for the attack on Wytschaete and Black Line North of the 25th Division’s sector; and one in reserve to the 2nd ANZAC Corps. All Tanks started off with the exception of those in Corps reserve, which moved off one hour later. Of the first two Sections, one Tank reached the Black Line after dealing with Wytschaete; and of the remaining seven, one became ditched in No Man’s Land and two in the German front system, while four operated between the Red and Blue Lines, which were intermediary objectives. Tanks of No. 5 Company, which were in Army reserve, received orders about 11.40 a.m. to co-operate with the 2nd ANZAC Corps in the attack on the Oosttaverne Line. One Section went South of Messines and the other two North of it. All three had to establish touch with their Infantry on the West of the ridge where they would shake out into attacking formation. The Southern Section arrived well in advance of the Infantry and considerably aided them in capturing their line and covering their consolidation. It was while thus engaged that Lieut Vans Agnew distinguished himself by conspicuous gallantry under hot fire. His Tank was set on fire by the enemy shelling and some members of his crew (notably Cpl BA Tait MM) set to work with Pyrenees to extinguish the flames. This necessitated moving about in the open under heavy and direct machine gun fire and fairly heavy shelling. Though bullets and splinters were hitting the ground all round and splashing against the side of the Tank, they continued and succeeded in putting out the fire and subsequently rallying the Tank. Lt Vans Agnew and Cpl Tait received immediate awards of the MC and bar to the MM respectively.