Hache’s plan was adopted, to be prepared for the attack ultimately made on 25 September 1915. The saps were dug by parties from the infantry, including men who were to make the attack. Vincent Martin, of the 119th Regiment, described the saps:

Initially underground saps starting from the first line trench about twenty to twenty-five metres apart beneath a thickness of 50cm of earth and driven to emerge in front of the enemy roughly within twenty-five metres of him; from each sap we could only emerge one man at a time. In advance of the excavation work, the enemy is warned by the spoil heaps and is wary of our intentions…⁴

As the saps got closer to the German lines, several men were killed or wounded each day by hand grenades, rifle grenades and mortars. During the sapping underground sounds were heard, but the Germans do not seem to have mined against the saps. By mid-September there were frequent grenade fights between the sap heads and the German trenches. It is not clear, however, exactly how the Russian saps were intended to be used in the attack. Although Martin refers to emerging from the saps, the attackers were to launch from the parallels. The records contain no reference to opening the saps into the sunken road with charges, bored or otherwise, and it is not clear when or how the saps were opened. On the night of 23 September, engineers attempted to place explosive charges beneath the German wire, which the artillery had not sufficiently gapped. The Engineer Companies 3/1 and 3/1 bis were to place long charges (like Bangalore torpedoes), but the saps were not sufficiently advanced. Only five could be charged and only one fired successfully, blowing a breach of 7m. The failure of the others was attributed to the appalling weather, which was wet and stormy. The operation was postponed to the following night, when seventy-two charges were taken into the saps, pushed or carried by engineers described as crawling up the saps. Of these fifty blew sufficiently to allow the passage of troops through the wire.⁵

The preparatory bombardment began on 19 September, but as the saps progressed the French artillery was not able to fire on the German front line, owing to the danger to the men digging the saps. Martin described how the Germans took refuge in their front line from the bombardment on their rear and an anonymous officer of 28th Regiment told how from their own lines they could see shovelfuls of earth being thrown out as the Germans repaired their trenches at leisure. On 24 September, the front line and saps were evacuated in order to bombard the German front line briefly. On 25 September the parallels and open saps from which the attackers were to leave were packed with troops waiting to attack and flooded by heavy rain. The same officer says that there were so many men in the new positions that it was impossible that the Germans were not aware of them. Corporal Paul Andrillon of the 119th Regiment was optimistic, however:

…at about 1100 we occupy the saps, the spectacle is superb, on all the points of the plain our guns are raging, impossible to distinguish anything of the Boche’s, there is only smoke, everyone has confidence in the outcome of the attack.⁶

Zero hour was 1235. Ten minutes before, the French discharged flame throwers from the front line about every 30m along the frontage of the attack. In places there were enormous flames and thick plumes of black smoke, but the fire was not spread everywhere. Paul Andrillon described the moment of attack:

…advance. No sooner got out, the Boche machine gunners in the front line spray us with a rain of bullets. I managed 10 metres on my feet and then collapsed knocked down like a sack of potatoes.⁷

The war diary of the 24th Regiment reported the fate of the first wave:

All who left the saps and parallels were mown down… The wounded of the first, second and third waves fell into the heads of the saps and the parallels… The obstruction of the communication trenches is extreme; orders and information arrive only very slowly.⁸

The leading elements were stopped dead with heavy losses. Units then became completely mixed up, the following waves crammed into the saps and parallels were unable to advance.⁹ Vincent Martin took refuge in a shell hole:

The captain being wounded, it was impossible for us to try to get to our jumping off trench without getting killed, the enemy machine-guns and rifles are directed on anyone who raises his head. The other comrades lined up beside us, faces to the ground, are dead. The night comes, the able bodied combatants who had taken refuge in the shell holes crawled and dropped down into the sap heads which had been dug by each of us, but no sooner had I arrived but they were crammed full of dead and wounded. I spent the night on the corpse of a former comrade whom I turned over onto his stomach so that I could sit on his pack which he still wore on his back. What horror! At day break our stretcher-bearers clear the dead and wounded and us the survivors, imprisoned in these cursed saps, under fifty centimetres of ground, we took again our place as soldiers in the jumping off trench where we are now also regrouped. We can then witness the horrible spectacle of death that there is in front of us: three successive lines of corpses in horizon blue, face down, weapon in their hands, facing the enemy that killed them! One could not dwell on this failure…¹⁰

The French attack, which had as its objective the summit of the Vimy Ridge, was repeated the following day, gaining the sunken road, and during the following two weeks pushed further up the slopes to the ridge. Vincent Martin condemned the attack:

After a 72-hour bombardment, where all the available artillery is used to destroy all Germans found in front of us, it is still us, the infantry: men, NCOs and officers up to colonel, who will be put to death for the glory of our generals, incompetent mass murderers, and so very ignorant of the situation.¹¹

The Russian saps, and General Hache’s ‘new and very special process’, had not contributed to the attack as hoped. He had used siege methods to attempt to create a broad breach in the German defences, but had launched the attack before the breach was formed and failure resulted. On the same day as the launch of the Third Battle of Artois, 25 September, the British also used Russian saps at the Battle of Loos as a means of pushing the front line closer to the Germans so that the assaulting troops would have a shorter distance to attack. On the 15th Division front this was reduced to less than 200yds and on the 9th Division front, opposite the Hohenzollern Redoubt, it was 150yds. During the night before the attack the heads of the saps were opened out and linked to form a new trench from which the attack could be launched.¹² These to some extent helped the troops, giving them a shorter distance to cross, although the attacks were only partially successful.

In May 1915, Colonel Ernest Swinton RE at GHQ formulated a plan with Norton Griffiths to use deep tunnels to smuggle troops past the German defences:

The idea was that we should arrange for the sudden intervention of a useful force behind the German front. This was to be done by means of galleries started well behind our own front, driven at depth in the clay far below that of the enemy mine system, and then inclined upwards to break ground at night behind his front in different woods, where the exits would be boarded over and concealed until the moment for action, which would be when we made an attack on the surface. Then, when the enemy was fully occupied on his front, British machine gunners and sappers would suddenly appear from out of the earth in his rear, ‘shoot up’ his heavy-gun detachments and cut his communications.¹³

Such a scheme, implausible as it may sound, came close to execution on the Gallipoli peninsula, where there was significant experimentation in the use of tunnels to cross no man’s land. In the cramped positions around Anzac Cove, the development of a defensive mining system against shallow level mines was combined with underground sapping. At the Pimple, saps on either flank had been completed by the end of May and more were begun between them, with the intention of joining them with a transversal tunnel which would form a new front line when they were 90ft out. The first 14ft of the three new saps (later called B3, B5 and B6) were to be underground to pass beneath the built-up parapet of the Australian front line. The blowing of a Turkish mine at Quinn’s Post on 29 May, which alerted the Australians to the danger of countermining, caused them to modify the sapping operations and continue sapping by shallow tunnels. These had an average of 18in of head cover and, largely driven without timber supports, were Russian saps in all but name.

By opening recesses from the transversal tunnels in which sentries could be stationed they became a means by which the Australians could push forward their positions and improve their observation over the Turks.¹⁴

As the tunnels lengthened ventilation holes were drilled about every 45ft:

This was generally accomplished by means of an old bayonet on the end of a rifle. Owing to the presence of so many dead Turks in the ground through which we were tunnelling, these holes were very necessary. They also served to keep the drives at one level. At night time, great care had to be taken that they were blocked with sacking or something to ensure that no light was visible from above. (Lance Corporal Cyril Lawrence, 2nd Field Company, Australian Engineers)¹⁵