It’s a century, this June 7, since the British blew up Messines Ridge, part of the front line of the Ypres salient where they had been wedged against the Germans since the end of 1914.

The blast involved most of the 1,307,800 pounds of ammonal, dynamite, gun cotton and blasting gelatine TNT, amatol and other explosives that industrious British tunnellers had been quietly planting under the German lines since early 1916. They were planted in 25 caches; and of these, 21 were deliberately detonated to support a British attack on the night of 7-8 June 1917. Nineteen of them went off over a space of 30 seconds, representing – as far as I am aware – the biggest non-nuclear detonation in military history.

The craters are still there – I’ve stood in one of them – a testament to the power the British unleashed that night. And one of the un-detonated mines, reportedly under La Petite Douve Farm, is still there after a century. Just saying.

So opened what is generally called the Battle of Messines, designed to set the British Second Army up in positions where they could then crack the German defences around the Ypres salient. The ground was unsuited to trenches, and German defences relied heavily on pill-boxes, machine-guns, mines and barbed wire, set out in depth. They were almost impossible for infantry to tackle, even backed by artillery. This was where the British mines came in; and into the mix flowed some new tactics that the British hoped would overcome the practical difficulty of getting troops across a muddy battlefield swept by machine-gun fire.

General Sir Herbert Plumer intended to use most of these mines to support a ‘bite and hold’ advance some two miles deep along a front ten miles wide. The final objective was the Oostaverne Line, from St Yves to Hill 60 at the north end of Messines ridge. The New Zealand Division was given the task of first taking Messines village itself, then moving on to an intermediate objective known on planning maps as the Black Dotted Line. Plumer had every expectation. Gentlemen,’ he reputedly quipped at the final pre-assault conference with his commanders on 6 June, ‘we may not make history tomorrow, but we shall certainly change the geography’. By the early morning of the next day – 2 am – the New Zealanders were ready in the fire trenches, to New Zealand commander, Major-General Andrew Russell, a ‘cheery and confident’ bunch who, as he told Minister of Defence James Allen later, seemed ‘extraordinarily confident of success’.

At 3.10 am on 7 June, the British ‘blew’ the ridge. And all northwestern Europe trembled. The New Zealanders were close to the huge Ontario Farm mine. ‘It was a most terrifying sight,’ Alger Duffy declared later, ‘and I’m not keen on being as close to another of the same size . . . Gee, but she was a snorter.’ It was typical Kiwi understatement. Stunned observers were struck dumb by the raw energy the British unleashed that night. Nineteen of those immense charges tore Messines ridge asunder. German defences – the reinforced concrete pillboxes, the concreted dugouts and the observation posts on the ridge – vanished in a flash, hurled skywards on pillars of fire. British observers even saw a complete pillbox spinning skywards. Ten thousand Germans died in those moments – and some were found later without an apparent mark on them. Even the British took casualties as clods of earth came tumbling down well away from the ridge.

The cataclysm rolled over the New Zealanders. Duffy felt the ground ‘swaying & rocking so that I expected to feel it cracking beneath our feet’; C. A. Healey felt it as a ‘big earthquake’. Nearby villages were jolted violently, German troops in Lille, fifteen or sixteen miles distant, panicked as the ground shuddered beneath them. Even in London, munitions workers on the late shift paused as the ground trembled. Lloyd-George felt it in his Downing Street study.

As earth began falling from the sky, the New Zealanders ‘hopped the parapet’ and pushed forwards, keyed up to fight while the artillery erupted behind them, blasting high-explosive and gas shells into the German artillery positions located during the previous week. And so their part in the battle began.

For the full New Zealand story of that battle, check out my book The New Zealand Experience at Gallipoli and the Western Front, available in print online or from any good New Zealand bookshop.

Copyright © Matthew Wright 2017