During the opening bombardment, the Royal Artillery fired over 1.6 million shells. The intensity of the attack was unprecedented. It left a vivid impression on all those who witnessed it. British signaller Harry Wheeler recalled the deafening noise the artillery made.

The firing was going on for weeks beforehand, on and off, and getting heavier. But the bombardment, when that started, it was what I always called the dance of hell. It was Boom! Boom! Boom! Boom! Boom! Boom! Boom! Boom! Shells bursting all the time, you know, guns firing, rather, all the time. It was a dance of hell, right enough. Those poor boys who had to go through it! My God, I shall never get it out of my memory. Yes, the dance of hell.

And for Royal Flying Corps pilot Cecil Lewis, the sight of so many guns in action remained clear in his mind long afterwards.

When you had to go right over the lines, you see, you were midway between our guns firing and where the shells were falling. And during that period the intensity of the bombardment was such that it was really like a sort of great broad swathe of dirty-looking cotton wool laid over the ground. And so close were the shell bursts – and so continuous – that it wasn’t just a puff here and a puff there, it was a continuous band. The whole of the ground beneath the darkening evening was just like a veil of sequins which were flashing and flashing and flashing and each one was a gun.

Stephen Westmann was a German army officer who lived through the barrage

We were under incessant bombardment. Day and night, the shells, heavy and light ones, came upon us. Our dugouts crumbled. They fell upon us and we had to dig ourselves and our comrades out. Sometimes we found them suffocated, sometimes smashed to pulp. Soldiers in the bunkers became hysterical. They wanted to run out and fights developed to keep them in the comparative safety of our deep bunkers. Even the rats became hysterical. They came into our flimsy shelters to seek refuge from this terrific artillery fire. We had nothing to eat, nothing to drink, but constantly, shell after shell burst upon us.

On the eve of the battle, the attacking infantry troops were moved up to the front line. British private Reginald Glenn recalled the feeling as they went forward.

We didn’t know until the actual day that we were going in. We went in at night and we got so far in and then were told no smoking. Everybody had got their big overcoats and a haversack with rations in and everybody was helping to carry something as well. We just went in and relieved the regiments that were in. They came out of one set of trenches; we went down the others because with having all your accoutrements there wasn’t room to pass one another. I suppose we were a bit worried about what was going to happen because the night before we’d been writing letters home…

Many of the men had a heartening tot of rum as they waited for zero hour; some had several. But Donald Murray decided it was best to abstain.

The previous night at about 12 pm, each dugout had a stone bottle of rum put into the dugout – a gallon bottle. And nearly every man was drunk, blind drunk. I thought to myself, ‘This looks to me like a sacrifice.’ And I never touched any; I didn’t have a single drink. I determined to keep my head – and it’s just as well I did.

In the lead up to the infantry assault, a final heavy bombardment was made on the German lines. Royal Garrison Artillery officer W Walter-Symons described it.

At 05.30 the barrage came down. It consisted of light artillery on the front line coupled with light Howitzers. Three hundred yards beyond that came down the heavier natures. The 6-inch, the 60-pounder, the 8-inch, the 9.2s and the 12-inch and the 15-inch Howitzers were allotted special targets and strong points such as fortified villages. Within a few moments, the air vibrated with the concussion.

Zero hour was set for 7.30am on 1 July. As it approached, the men prepared for battle in crowded front line trenches. Private R Mason was among them.

We’d reached our attacking positions overnight and we were all ready for the assault an hour before we had to go. And we sat down crouching in the shallow, narrow trench almost shoulder to shoulder. I was next to the officer and got him something out of his own haversack because he could not turn round to the back. He said, very shortly, only five minutes to go…

Finally, the barrage lifted and the moment came for men like Private Arthur Pearson to go over the top.

We were anxious to be over the top and at Zero Hour, 07.30, everybody, we climbed out of the trenches. Two platoons in advance had been and laid on a white tape and they formed the first wave. Every man climbed out of the trenches at the whistle of the officers and not a man hesitated. But I was lucky. I was in a part of the trench where the parados had been battered down as Jerry sought for a trench mortar. When I ran up the rise out of the trench I was under the hail of bullets, which were whizzing over my head. But most of our fellows were killed kneeling on the firestep – on the parados.

Once out of the relative safety of their trenches, the attacking troops had been ordered to advance slowly towards the Germans in long lines. Maurice Symes – like many others – didn’t think much of this order.

It was just as if we were at… that almost was like a training exercise, which was really, I suppose, absolutely mad when you come to think of it. We were just in extended order with everything on your back, your rifle and bayonet, your entrenching tool and everything else. We were just walking, straight towards the German lines in extended order. Well, we were sitting ducks all the way. Our earlier training you see for open warfare, run so far then lie down and then run a bit further. But this was just walking, straight into the death trap, hundreds of us. Just hopeless.

Officer Alfred Irwin approved an unusual initiative by one of his officers to motivate the troops under his command.

Well Captain Nevill was commanding ‘B’ Company, one of our two assaulting companies, and a few days before the Battle of the Somme he came to me with a suggestion, that, as he and his men were all equally ignorant of what their conduct would be when they got into action, he thought it might be helpful, as he had 400 yards to go and knew that it would be covered by machine-gun fire, it would be helpful if he could furnish each platoon with a football and allow them to kick it forward and follow it. And that was the beginning of the idea, and I sanctioned that on condition that he and his officers really kept command of their units and didn’t allow it to develop into a rush after the ball. If a man came across a football he could kick it forward but he mustn’t chase after it, and I think myself it did help them enormously, took their minds off it. But they suffered terribly. Nevill and his second captain were both killed.

As the men crossed no man’s land, many, including Private Mason, became separated from their comrades.

My officer called across to me and said, ‘You stick to me and I’ll stick to you.’ I said, ‘Right,’ but immediately lost sight of him. I didn’t know what happened to him but he was wounded. Very soon I found I was going forward and not many were around me. At this time, a hare ran along in front to my great surprise, with its eyes bulging or apparently bulging in fear – but I didn’t think it was half as frightened as I was.

When those who had survived the crossing of no man’s land neared the German front lines, it became clear why they were so few in number – the defences were still intact. Arnold Dale of the York and Lancaster Regiment couldn’t believe that the deadly barbed wire was untouched.

As we moved forward, having got through our own wire quite easily, and approached the position we were to take up prior to our own bombardment lifting so that we could move forward into the German trenches, we saw what a terrible job it was – or would be – to get through the German wire. It was so thick, it looked solid black. I can’t really say that I could pick out any single strand; it was so solid that in my opinion a rabbit couldn’t have got through it.

The men had been told that the initial bombardment would eliminate the German positions. But it had failed to do so. Walter Cook, of the Royal Army Medical Corps, explained why.

The Germans were down in 30-foot dugouts whilst the bombardment was on. I have personally been in one and they were so constructed that any bomb thrown down if there was Germans in there, it would only go down so far, because it would then go off at a traverse down to the 30 feet. They had selected machine-gun posts and they just mowed down the infantry. And we had a big job on.

Frank Raine, of the Durham Light Infantry, remembered how this affected the attack in his sector.

We were told that there was going to be this bombardment that would knock hell out of the Germans and all we had to do was get up and walk across – and we only had to walk, on no account had we to stop for anything – just walk straight through to Berlin. And there wasn’t one of us in our battalion that ever got to the German lines. You couldn’t! It was absolutely impossible. The jokers, they never learnt. The Germans had these deep dugouts; they were safe as the bank. They were 30 feet down!

The Germans opened up terrific and accurate fire on the advancing British infantry, as Stephen Westmann remembered.

Then the British Army went over the top. The very moment we felt that the British artillery fire was directed against the reserve positions, machine gunners, German machine-gunners, crawled out of the bunkers, red-eyed, sunken eyes, dirty, full of blood from the blood of their fallen comrades, and opened up a terrific fire. The British Army had horrible losses.

Ernest Bryan commanded a Lewis gun team during the attack. He and his men made it through no man’s land – but were met by strong German fire.

The majority of their wire wasn’t cut at all, not by our artillery at all, not even by our trench mortars. So what happened, all that was in there, there was no riflemen but there’s machine-gunners. When I say the machine-gunners, I don’t mean Lewis gunners, machine-gunners who had static machine guns; you could fire 250 rounds on one belt. Well, the first thing I did, I put me gun on me shoulder and I sprayed the top. Ah! The German gunner went down, whether he was hit or not I didn’t know and I didn’t care. He was down, they were all down.

Nearly 40,000 British soldiers were wounded on 1 July. Maurice Symes, a private in the Somerset Light Infantry, was one of them.

Well we just scrambled over the trench and walked forward. I could see people going down all the way round you know getting shot. It wasn’t a very pleasant feeling. And then I got hit myself, it knocked me out. They said I was more surprised than anything else, really. I wondered what the devil had happened. It felt just like somebody had kicked me in the stomach; a funny sort of feeling but I knew couldn’t go any further. I just dumped everything except my water bottle and crawled into a shell hole and stayed there for a bit. I had a bullet straight through, then I got into a shell hole for a bit of shelter and got another shrapnel wound there.