"You can't make an omelet without breaking eggs, to use an old cliché… and this is a nasty modern war with tremendously destructive weapons.

"In order to learn how to apply those weapons to your own benefit, you're going to take huge losses. This is the dilemma of the First World War. What I'm trying to point out is that the old image of the unthinking butcher and bungling generals who are not thinking about what they're doing is totally untrue.

"There are stupid generals, there were lots of stupid generals in the First World War, but there were also intelligent, highly motivated generals and soldiers who are thinking of what they're doing. The commanders in chief on both sides make huge mistakes and continue to make them. But they are themselves learning.

"In the British and Commonwealth forces, I think the Command is beginning to be decentralized in the sense that Haig leaves his subordinates, for instance, to fight the battle to a much greater extent by the end of the war than he does even in 1916. That's one process that's got to be learned. The second point, in this sort of learning curve, if you like, is the people don't learn everything overnight. It's trial and error – and that above all, is what it's about. And there were lots of errors and lots of endurance needed in order to see this learning curve through.

"So it is a bleeding curve, but the proof of the pudding is in the eating in 1918, when the formula, to my mind, is much better balanced. The army is able to win."