The five tunnels on the 31st Division front were opened at 6.30am, one hour before zero, and at least one contained emplacements for Stokes mortars. The failure of the attack meant that the tunnels became blocked with wounded and never functioned as a link to the German line. On the northern flank John sap, 458ft long, was opened to form a communication trench called ‘Russian Trench’ into a mine crater in no man’s land. Many of the 12th York & Lancaster sheltered in this trench when unable to cross no man’s land.³¹ From the southern tunnel in the 31st Division, Bleaneau, the mortars each opened fire with 150 rounds at 7.20am, but the rate of fire was so high with this weapon that their ammunition was expended within eight minutes. By 7.28 there was no fire on the German front line, and German survivors were manning their parapet ready to repel the attack. The opening of the sap attracted grenades and the mortar commander was killed. The tunnelling officer at the end of this sap, Captain Alexander Donald, believed that machine guns would have been more effective in these forward posts given that the German front line was still capable of resistance.³²

In fact the 4th Division, next in line to the south, placed Lewis machine guns in its four sap heads instead of mortars. However, of four Lewis gun teams in the head of Cat Street and Beet Street tunnels, two were put out of action by a British shell during the final bombardment of the German front line shortly before zero. The remainder were all casualties by the early afternoon of 1 July, especially from German grenades, with the exception of one officer and three men.³³

After hearing Donald’s account, an assistant of Brigadier Harvey reported that the ends of these saps, which were very close to the German lines, should have been used to blow charges to deal with the resistance in the enemy front line: ‘The failure to utilize the northern saps for blowing destructive & demoralising charges at the moment of attack appears to have been an error.’³⁴

Prior to the attack the divisions attacking on the northern front had opposed firing mines from the ends of the saps as they believed that the artillery would have dealt with the resistance in the front line and they would not be necessary.³⁵

On the 29th Division front, of three saps driven either side of the Hawthorn mine, two reached within 30yds of the German front line and contained Stokes mortar positions. The third, Sap 7, connected a sunken lane which ran across no man’s land midway between the British and German lines. This was used to file the two leading companies of the 1st Lancashire Fusiliers and a mortar team into the cover of this lane prior to the attack. An official cameraman, Geoffrey Malins, also passed through Sap 7 to film the men waiting to attack:

The tunnel was no more than two feet six inches wide and five feet high. Men inside were passing ammunition from one to the other in an endless chain and disappearing into the bowels of the earth.

The shaft took a downward trend. It was only by squeezing past the munition bearers that we were able to proceed at all, and in some places it was impossible for more than one to crush through at a time. By the light of an electric torch, stuck in the mud, I was able to see the men. They were wet with perspiration, steaming, in fact; stripped to the waist; working like Trojans, each doing the work of six men.

The journey seemed endless. I could tell by the position that I was climbing. My guide was still in front, and letting me know of his whereabouts by shouting: ‘Straight ahead, sir! Mind this hole!’

The latter part of the shaft seemed practically upright. I dragged my camera along by the strap attached to the case. It was impossible to carry it. We were nearing daylight. I could see a gleam only a few feet away. At last we came to the exit. My guide was there.

‘Keep down low, sir. This sap is only four feet deep. It’s been done during the night, about fifty yards of it. We are in No Man’s Land now, and if the Germans had any idea we were here, the place would soon be an inferno.’

‘Go ahead,’ I said. It was difficult to imagine we were midway between the Hun lines and our own. It was practically inconceivable. The shell-fire seemed just as bad as ever behind in the trenches, but here it was simply heavenly. The only thing one had to do was to keep as low as possible and wriggle along. The ground sloped downwards. The end of the sap came in sight. My guide was crouching there, and in front of him, about thirty feet away, running at right angles on both sides, was a roadway, overgrown with grass and pitted with shell-holes. The bank immediately in front was lined with the stumps of trees and a rough hedge, and there lined up, crouching as close to the bank as possible, were some of our men. They were the Lancashire Fusiliers, with bayonets fixed, and ready to spring forward.³⁶

The Germans, having been warned by the detonation of the Hawthorn mine at 7.20am, were ready when the Lancashire Fusiliers attacked and opened heavy fire on them as they left the cover of the lane, completely stopping their attack.

The 29th Division wished to keep the tunnels clear for establishing secure signals communication with the captured position and supplying water and ordered before the attack: ‘The tunnels will only be used for runners and for getting telephone wires and water pipes forward. They will not be used as communication trenches.’³⁷

Sappers were stationed in the tunnels with a water pipeline ready to run into the captured German front line.³⁸ Pioneers were detailed to dig trenches to link the tunnels, named First Avenue and Mary, with the captured trenches, but found the British trenches congested with wounded and dead from the failed attack and the German barrage. They found the tunnels impossible to pass through as they were full of wounded, with signallers and orderlies trying to get through.³⁹

Saps in front of Thiepval, Ovillers and La Boisselle were the task of 179 Tunnelling Company. On the 36th Ulster Division ten saps were run from the front line north-east of Thiepval Wood (see map). The intention was for each of the ten tunnels to have two mortars, firing from T-headed emplacements. On 1 July, mortars fired from at least six of the saps at five minutes before zero and, under the cover of this fire, the Ulstermen left their trenches to lie down in no man’s land about 100yds from the German lines. This fire and the British bombardment had a powerful effect on the German defenders and the forward waves of the 36th Division were able to take the front line and push deep into the German positions. During the day, however, the effects of the German counter-barrage and the failure of the units on either side of the division reduced the gains to the German front line only, where the attackers could not be resupplied. None of the ten tunnels approached close to the German front line and attempts to connect them with trenches across the remaining distance proved impossible owing to German fire. At 8.40am a company of the 16th Royal Irish Rifles Pioneers was sent to dig a trench from the end of Sap No.5, which was about 900ft from the German line (about 320ft north-west of the present day Connaught Cemetery). They made several attempts but were shot down each time they left the end of the tunnel, losing about twenty men before they could begin.⁴⁰ Following the attack, the Division recommended narrowing no man’s land before an attack and using Russian saps running across no man’s land:

The 36th Division successfully crossed a No Man’s Land of 400 yards but found the passage of reinforcements and runners afterwards of the greatest difficulty. Parallels should therefore be pushed forward to 200 yards or even nearer and should be supplemented by Russian saps as far as possible across No Man’s Land. These saps should be close below the surface so that the top can be thrown off; the roots of the grass serve as a useful guide. Deep underground tunnels of any length are not desirable.⁴¹

On the 32nd Divisional front, two medium trench mortar emplacements and two communication tunnels, Inverary and Sanda, were prepared. The attack was not a success, with troops in the Leipzig Salient again beleaguered in part of the front line, but in these circumstances the tunnel positions were found to be of value. The two mortar positions extended to within 111 and 115ft of the German line and contained emplacements for 2in trench mortars firing a 60lb ‘toffee apple’ projectile. The Division reported favourably on the value of the tunnelled positions despite some difficulties:

For two days the guns in these Saps fired without having any German shells near them. On the third and fourth day of firing they were heavily shelled. Our own gas, when liberated from the front line, slightly gassed two of the gun team waiting in the Saps and some time elapsed before these positions were again fit for use. … As battle positions they were undoubtedly a great success and enabled targets to be engaged 500 yards behind the German front line.⁴²

After initial success, troops were forced back into the Leipzig Salient, which was packed with troops cut off from their own lines by the German fire in no man’s land. Inverary and Sanda were driven to within 86 and 170ft of the German front line and the 17th Northumberland Fusiliers Pioneers were ordered to open them as soon as possible after the assault and dig a trench to link them to the German line. Such was the congestion of dead and wounded and the heavy fire in the British trenches that the platoon responsible for Sanda tunnel, under Lieutenant H. Shenton Cole, was unable to even reach it until about 4pm:

Cole found the sap choked with dead and wounded men of the assaulting battalions, who had crawled in there for safety from the incessant machine-gun and whiz-bang fire which swept the whole front. A few men were sent along the sap who, with great difficulty, crawled through among the dead and wounded and broke through at the far end, which had been blown in by a chance shell. Having thus ascertained the point from which the trench was going to start, Cole led out the rest of the platoon across the open, going warily from shell-hole to shell-hole under heavy fire, till he had men distributed in a rough line, four men in each shell-hole from the sap end to the enemy’s front line opposite, which was now in our hands. The men worked towards each other, two each way, and thus, with the loss of only two or three men wounded, the trench was completed…⁴³

The communication opened up through Sanda tunnel enabled water and supplies to be got into the Leipzig Redoubt and wounded men to be evacuated. Hance, commanding 179 Company, later claimed credit for the successful operation of Sanda tunnel in supplying the Leipzig Salient, which he had constructed double width, with a wooden partition down the middle to allow two-way passage:

Sentries posted at each end controlled the traffic, and, whilst it might be inhuman to prevent a wounded man from sheltering in one of these tunnels, it is no great hardship to ask him to ‘keep to the left’. At any rate the tunnel was an unqualified success, and elicited the highest commendation from the Brigadier... [Goring-Jones, commanding 146 Brigade]. Although it was of double width it only received one direct hit, which damage was repaired at night. (Major H.M. Hance)⁴⁴

South of the 32nd Division, 8th Division faced the fortified village of Ovillers, flanked by the open expanses of Nab and Mash Valleys, which were swept by fire from the Leipzig Redoubt and La Boisselle. On the boundary of two Divisions, south of the Leipzig Redoubt, a tunnel was driven 50yds into no man’s land from Mersey Street and emplacements constructed for four Vickers machine guns. These guns were to cover the attacking troops by firing up Nab (later known as Blighty) Valley, where no man’s land was a quarter of a mile wide, to deal with positions and German machine guns where no attack was to be made. After the first line was taken the machine gunners were to break out of the tunnels to further assist the advance. Initial waves in the north had some success on 1 July, but at 10.55am the commander of the machine gun section in the Mersey Street tunnel reported to his company commander that:

...he fired from the tunnel position 6,000 rounds sweeping the German front line & up towards Farm De Mouquet. He had 5 men overcome and faint with cordite fumes. He then started breaking through the tunnel and experienced considerable difficulty. At about 9am he had broken out in two places. All this time the enemy trenches were difficult to see owing to the smoke & haze. He was under the impression that our advance had been a success. 2/Lt Hampton took two guns out & disappeared. It was afterwards found that he & practically all the gun teams of his two guns were killed or wounded 30yds from the tunnel. 2/Lt. Steel not knowing this ordered his teams out; the first 3 men were killed & the gun had to be left a few yards away in the open. He then stopped more men leaving & with his one remaining gun worked round to the Nab & learnt that we were not holding the German front line. His men being exhausted he put them in a dugout & reported to me for orders. (Captain J.F. Jessop Weiss, MGC)⁴⁵

Facing Ovillers the 8th Division had two communication tunnels, each with four Stokes mortar positions, prepared by 179 Tunnelling Company. Waltney, through chalk, ran 520ft with its east end 380ft from the German line, while Rivington was cut through clay and had been driven further, 600ft, and closer, 40ft, to the German front line. Hance did not construct these double width as he had Sanda, but the standard dimension of 5ft 6in in height and 3ft 6in wide at the floor and 2ft 6in wide at the roof, a size that he felt was to narrow.⁴⁶ The ends of both were to be opened directly the German front line had been taken by blowing explosive charges rather than breaking out with picks, and it was thought that the crater opening would resemble a shell hole and so not arouse suspicion. The mortars covered the movement of the infantry into no man’s land, as in the 36th Division. However, as the troops rose to the attack at 7.30am, from Ovillers, La Boisselle and the German second line, a terrific volume of machine-gun and rifle fire poured into the attackers and, as they neared the German front line, the artillery barrage came down on no man’s land. A handful of the 2nd Lincolns, on whose front Waltney tunnel was situated, got into the German front trench, but were forced out into no man’s land. Waltney was opened but seems to have played little or no part. Rivington, on the front of the 2nd Royal Berkshires, was not opened as the infantry were unable to reach the German front line. In the broad expanse of no man’s land, where 8th and 34th Divisions advanced with very heavy losses up Mash Valley, no saps seem to have been used, although Sappers of 207 Field Company reported working on them in May between Argyll Street and Dorset Street trenches, and north of Keats Redan they seem to have been given up.

Opposite La Boisselle one Russian sap was prepared, although without trench mortar emplacements, which were instead constructed in the British lines (see map). The tunnel was started from Kerriemuir Street, aiming at the northern end of the Schwaben Höhe (the Lochnagar mine was under the southern tip). It was driven 410ft through chalk, reaching to within 120ft of the German line. The last 150ft were worked with the bayonet only and at night German patrols were heard constantly overhead. Hance constructed it to the standard 3ft 6in width, with 12 to 14ft of overhead cover.

A platoon of the 18th Northumberland Fusiliers Pioneers under Lieutenant Nixon was to open up the Kerriemuir Street tunnel and dig a communication trench connecting it to the German front line. The tunnel end was about 470ft from the Lochnagar mine charge: his orders were therefore to shelter twelve of his men in the end of the tunnel nearest the British line until the mine had detonated and then, after checking that the gas was safe, begin breaking open the remaining 2ft of head cover. After the last wave of the 102nd Brigade attack had passed he was to call forward the rest of his platoon, who were sheltering in a mine shaft, and construct two ramps out of the tunnel. After the last wave of the 103rd Brigade had passed he was to begin digging the trench to the German front line. On arriving at the tunnel the night before the attack, however, Nixon was told by Hance that he would have to break through 12ft of cover rather than 2ft. Nixon therefore started work at midnight and by 8.30am had only broken through sufficiently for the signals cables to be passed through. In the meantime, the attacks by the two brigades had been made and had gained a foothold only around the Schwaben Höhe. By 10am men were able to pass through the tunnel, but the work was badly impeded by wounded coming back through the tunnel and stores being brought forward. The communication trench reached the German front line by 7pm. Hance witnessed the congestion in the tunnel:

This tunnel was immediately used as a communication, I myself saw with what eagerness, by parties carrying bombs and other supplies up, & by wounded coming down. Consequently it was immediately blocked, and I am convinced, that such tunnels, though altogether admirable in conception, have been made too small, and, to be efficient, must have two roads for traffic both ways.⁴⁷

The 9th Cheshires were sent to reinforce the troops which had gained possession of the Lochnagar crater and the remains of the Schwaben Höhe. The commander of D Company arrived at about this time:

The mine tunnel (which had been opened out to the captured German line) and our front near to it, I found to be entirely blocked by wounded and unwounded. I had this trench and tunnel cleared and posted Sentries at both ends and at head of rear communication trench to regulate all traffic. (Lieutenant A. Vincent Ward, 9th Cheshires)⁴⁸

The commanding officer of the Northumberlands Pioneers stated that the whole battalion passed through the tunnel. Although it was claimed in the official history that this tunnel connected into the Lochnagar crater, and included a map showing this, the tunnel and the communication trench reached the German line about 330ft north-west of the crater lip.⁴⁹ As at the Leipzig Redoubt, this tunnel served its original purpose in reinforcing the position at the critical period after it was first gained, although the battle had not gone at all to plan. The 34th Division orders for the attack contained no reference to the Kerriemuir tunnel, perhaps for the sake of secrecy, and the commander of the 15th Royal Scots later complained that the tunnels were never made known to them and had they been told of them they might have come into use sooner.⁵⁰ On the whole, Hance’s view of the Russian saps that his Company had constructed was that they needed to be wider and partitioned to allow two-way traffic, otherwise:

...their utility was very limited. They were almost immediately blocked with wounded, and I saw fresh troops etc coming up passing over the bodies of their wounded comrades, which was certainly not good for morale.⁵¹

The 21st Division had two saps across no man’s land. One, Dinnet Street, south of Sausage Valley, had been prepared during September and October 1915 on the orders of General Maxse in the expectation of a general advance following the Battle of Loos.⁵² This was broken open and converted into a trench during the night before the attack and used by the leading attacking companies of 10th King’s Own Yorkshire Light Infantry to get forward of the British wire five minutes before zero. This did not prove sufficient to overcome the German machine gunners, who emerged from their dugouts in time to bring heavy fire on the attackers.⁵³ The other sap, Purfleet, seems to have been of no use to the 4th Middlesex and 10th West Yorkshires.

In the southern part of the Somme, especially a wide front of Hickling’s 183 Tunnelling Company, there was a very different outcome on 1 July. Along the fronts of the 7th, 18th and 30th Divisions were eighteen Russian saps, which were designed to be broken out for communication purposes, but many of which were also used to blow comparatively small charges. Nine or ten of the saps which ran through the surface clay were extended to the German front line by silently using an auger to cut out a wide diameter bore hole, which was charged with 200 to 500lbs of explosive in a method resembling the German sapping and mining attacks of the winter of 1914–15. The risk involved with this is illustrated by an encounter of the commanding officer of the 6th Royal Berkshires with one of Hickling’s men prior to the attack:

The officer responsible came to me very agitated running out of our end of the trench to say the whole show was given away as his augur head had pierced through into an officers’ dug out & he could hear every word they were saying. He thought they must know and all was discovered. On enquiry I elicited from him the fact that there had been no interruption in their talk – no dead silence – no raised voices – so was able to assure him that according to human nature all was well!! I identified the spot later and it was quite true that he had just pierced through into an officers dug out! (Lieutenant Colonel B.G. Clay)⁵⁴

The attacks of the 7th and especially the 18th and 30th Divisions and the French to their right were markedly successful with objectives quickly gained. The reasons for this success were broadly threefold: the positions to be assaulted were not so easily defended, the Germans had fewer troops in their front lines and the British learnt more sophisticated artillery and counter battery tactics from the French and benefitted from their gun batteries. The saps played a role in this success by bringing firepower to bear on the German front line in the first minutes of the attack. Four of Hickling’s Russian sap galleries on the 18th Division housed forward machine-gun emplacements and two also contained very large flamethrowers, in the first British use of this weapon. Four flamethrowers were intended to be used on 1 July, but two galleries where installation was prepared, south-west of Mametz, at Kiel Trench, and between Carnoy and Casino Point, were damaged by shellfire. The two remaining were immediately to the left of the mine crater field at Carnoy and shot flame for a distance of 282 and 261ft in an attack which was effective, yet also localized.⁵⁵

In contrast to the north, where the congestion caused by the failed attacks and heavy German barrages greatly hindered the opening and operation of the saps, Hickling was able to open his saps for traffic very quickly. On the 18th Division he blew the mines and charges at 7.27am and then rapidly opened the tunnels for traffic through ‘manholes’, in one case immediately afterwards, in three cases at 7.35 and the fifth at 7.45am. Hickling then had a larger exit made into the craters blown at the ends, the quickest of which opened at 7.55. Two others were delayed until 2pm, either owing to damage from German shellfire or the greater depth of the tunnel.⁵⁶ Even these delayed openings were much faster than the connections made at the Leipzig Salient and La Boisselle. Although Hickling’s men were hampered by the German barrage, it was not as heavy as in the north and there were not the streams of wounded and men trying to get forward, as the waves had succeeded overland and had moved on to their objectives. Paradoxically, however, had the attack been held up at the German front line then the tunnels might have been more important to the attack. Hickling himself pointed out that the Russian saps had little role in the success:

These saps in the event were very little used for communication, as intended, as the advance on the whole length of front prepared by 183 Company was successful. If the attack had been only partly successful as in other places, they would undoubtedly have been very valuable.⁵⁷

On the front of the 30th Division at Maricourt, Hickling also tried using hydraulic forcing jacks or pipe pushers to drive tubes of explosive through the ground. This device, which had failed at St Eloi on 27 March, was also found unreliable where the flinty chalk of the Somme was close to the surface and was experimented with at Ovillers by the 8th Division until the commanding Royal Engineer had observed the pipe emerging from the ground in no man’s land. Only one of Hickling’s was found satisfactory on 1 July, blowing a long narrow crater 180ft long, 15ft wide and 7^1/2ft deep. Another intended to be 220ft long only worked in the first and last 50ft, the other sections either failing to explode or only blowing a trench 5ft wide by 2ft deep.⁵⁸

Soon after 1 July, Harvey’s assistant, Stokes, visited the Somme Tunnelling Companies. Trower’s 252 Company was, he reported: ‘…rather depressed now owing to the uselessness of its 10,000ft of galleries in assisting the attack and will naturally work now with poorer spirit.’⁵⁹

Stokes concluded that the northern saps should have been used for a greater number of charges, as were Hickling’s, rather than, as at Serre, trying to dig right up to the German trench. Whereas most of Hickling’s charges had been small he felt that the charges should have been larger, that is, the size of the Hawthorn mine. The purpose of the charges was to deal with the German front line, to assist the infantry in getting across no man’s land and to prevent the tunnel openings having grenades thrown into them:

The comparatively long distance between the lines in this sector led to the failure of the infantry attack, although the guns & infantry did all that was possible against skilfully sheltered enemy. But this long distance was also the R.E. opportunity, owing to the surprise that was possible in carrying out gallery schemes. Under the methods followed, too much thought seems to have been given to facilities after occupation of enemy lines & too little to the means of getting infantry across 200 yards of good field for machine gun fire. Where lines are so far apart, it is naturally the front line that costs most. The failure to utilize the northern saps for blowing destructive & demoralising charges at the moment of attack appears to have been an error.⁶⁰

Preedy reported on 9 July that the shallow galleries should be ‘constructed wherever possible.’ He specified the form that they should take, with entrances in the support trench rather than the front line, in pairs 50ft apart to avoid being damaged by the same shell, but linked for ventilation, and 10 to 15ft of overhead cover to make them safe from shell damage. He recommended following many of Hickling’s practices, including using a borer from the end of the tunnel, 50ft from the German line in clay or 90ft in chalk. The charges blown would quickly complete the trench into the German line and destroy barbed wire and dugouts. Emplacements for Stokes mortars and machine guns should be built at 30ft on the flanks of the tunnels; machine guns were more useful than mortars. Manholes or exits for the troops were needed for use before the tunnels could be opened into the craters. Tunnels to cross 200yds of no man’s land took two and a half to three and a half months to construct. They needed effective traffic control, ventilation and lighting.⁶¹ Although many of Preedy’s recommendations were to be taken up in 1917, an attempt to use four Russian saps, constructed by 174 Tunnelling Company, in an attack at Hamel on 3 September was unsuccessful. As on 1 July the fire on no man’s land was too heavy for Pioneers to link the ends of the saps to the German front line and the 39th Division was forced out of the German front line.⁶²

The Somme battle continued until November 1916, and the Battle of the Ancre, launched on 13th, was a major attempt to take the northern battlefield, where the attack had completely failed on 1 July. The front line at Serre and Beaumont Hamel had remained static until then and the saps dug for the 1 July and 3 September attacks were reused and improved. The problem with the Serre tunnels in particular was that the Germans now knew exactly where they were. The state of the trenches rendered four of the ten saps from Serre to the Redan completely inaccessible, but 252 Company had been maintaining the remainder since 22 July. The Germans went out at night into no man’s land to destroy them and in August and September blew fifteen charges against Grey, Excema, John and Bleaneau. On 8 September they smashed the whole of Bleaneau except the first 120ft. On 18th they blew a charge against Grey and then heavily bombarded the trenches; when eleven infantry went into the tunnel to shelter they were all killed by the carbon monoxide from the explosive. Orders to prepare the tunnels for the offensive were given and cancelled several times and 252 Company was working constantly to repair the tunnels owing to the frequency of bombardments and the very bad state of the trenches. For the Serre attack, by 31st and 3rd Divisions, Trower was instructed on 30 September to reopen John, Mark, Excema and Grey, his war diary commenting: ‘Very dangerous work & very short time given.’ There is no reference to using the tunnels as mortar or machine-gun emplacements as they had been on 1 July. They began work on 1 October, but the Germans blew the next day between John and Mark without damage, although ten infantry were gassed sheltering in Excema, of whom nine died. The entrances to Grey were twice smashed by shellfire.