Well, the capture of the strongpoints of Beaucourt and Beaumont Hamel would improve the Allied position on the Somme.

But really, the Battle of the Ancre was driven by pride, prestige and politics. Beaumont Hamel was one of the objectives on July 1, the first day of the Somme. Four and a half months later, it was still in German hands.

And a victory now, at the end of the fighting season, would stand the British Army in good stead for the coming year both with its Allies and with the politicians and public at home.

And so after a five-day barrage, at 5.45am on Monday November 13 1916, officers’ whistles sounded all along the 1,200-yard front held by the Royal Naval Division.

On the men’s left, Beaumont Hamel. Directly ahead, Beaucourt, 1½ miles distant, on their right, the barely discernible course of the swollen Ancre and what was left of the rail line to Arras.

At their side, six British divisions all smashing their way forward over craters where there had once been farmland and ruins where they had once been villages.

The Hood and Drake battalions made good progress – the preparatory barrage had largely smashed the German lines.

Not so Hawke and Nelson battalions, which ran straight into a German strongpoint they had no knowledge of. German machine-gunners cut them down. By mid-morning, neither battalion existed as an effective fighting force.

But then even for the battalions finding the going rather easier, the toll was fearful. The Hood was reduced to 300 men, Drake to an alarming 80. That these two battalions not only remained in the battle but continued to advance was largely down to the personal courage of the Hood’s commander, Bernard Freyberg.

He carried his makeshift force to within a few hundred yards of their goal, taking 400 prisoners to boot. A final concerted effort to reach Beaucourt shortly after mid-day by every battalion which were still battle-worthy was bloodily repulsed.

Divisional commander Cameron Shute decided only tanks could win the day. An hour before dawn on November 14, these modern miracles of warfare moved forward, guided by a junior naval officer.

A combination of German fire and Somme mud brought the armour to a halt, but the tanks did at least knock out the German redoubt which had inflicted so many casualties on the Hawkes and Nelsons 24 hours before.

Otherwise, it was left to the bravery of individual leaders to carry the attack forward once more. Again Bernard Freyberg came to the fore. Three times the attack he led faltered. Three times Freyberg, a champion swimmer, stood up and waved his men forward. Finally, on the fourth assault, enemy resistance seemed to melt away.

Men who minutes before had poured lead and steel into the attacking sailors now surrendered in droves. Perhaps 500 or 600 Germans emerged from battered trenches and shattered dugouts with their hands raised.

The enemy guns subjected the attackers to one last ferocious barrage which badly wounded Bernard Freyberg. Carried from the field of battle, he would subsequently receive the VC for his deeds on the Ancre. A generation later, he would lead the unsuccessful defence of Crete against Hitler’s airborne troops.

There was no end of praise for the rest of the Naval division. No army formation had advanced as far nor taken as many prisoners during the Somme offensive.

Not that Trevor Jacobs felt like celebrating. “I never saw anything so tragic,” he wrote as he marched back over the battlefield to Englebelmer. “It was a shambles, any amount of our brave fellows being all round in shell holes and with terrible wounds – some of them with half a head blown off, others without legs and arms, and others with numerous bullet wounds.”

The father-of-one was killed on the Ancre on February 4 1917 while leading a company of Hoods once again. He is buried four miles away at Queens Cemetery in Bucquoy alongside more than 700 other Allied fallen.