"What was it that made the battle of the Somme last as long as it did and what was the purpose of it.

"It's probably true to say that the men who fought it had never seen anything like it before. The Generals who planned it had no precedent. The other side of looking at it is more critical.

"This was not supposed to be an attrition battle, a battle to wear the other side down – it was stated as a breakthrough battle. But the longer the battle went on, the more evident it was that no breakthrough was possible, and yet the battle continued. In some ways it led to a redoubling of efforts; it didn't lead away from war, it led to its deeper, more profound, more vicious prosecution."